Abstract

The growth of single and multiple (three) ZnO/ZnMgO quantum well samples on sapphire substrates, through a two-step temperature variation growth of ZnO buffer layers by molecular beam epitaxy (MBE), were investigated. For single quantum well (QW) growth, the thicker first ZnMgO barrier layer about 220 nm on the high-temperature growth ZnO (HT-ZnO) buffer layer, accumulated larger compressive stress, to achieve higher quality ZnO/ZnMgO QW growth. In the temperature-dependent photoluminescence (PL) results, the obvious S-shape variation of emission peak positions presented the stronger exciton confinement ability of QW in the higher magnesium concentrations of ZnMgO barrier layer growth. Compared to the control sample, the quantum confinement resulted in blueshift PL peaks of QW samples at low temperature. The multiple quantum well (MQWs) structure increased the exciton confinement ability to enhance the light emission efficiency of the sample. The three ZnO/ZnMgO MQWs structures were found clearly by high-resolution transmission electron microscopy.

©2013 Optical Society of America

1. Introduction

ZnO has received considerable attention owing to its excellent emission properties in the UV region. ZnO is a direct band-gap material with a wurtzite structure, exhibits a wide band-gap of 3.37 eV, and has a large exciton binding energy of 60 meV at room temperature [13]. Based on these fundamental properties, ZnO has many applications in the short wavelength region, such as optically pumped lasers, UV light emitting diodes, detectors, solar cells, and gas sensors [25]. Moreover, the excitons in ZnO-based quantum well (QW) heterostructures exhibit strong stability, as compared to bulk semiconductors, owing to the enhancement of the binding energy at about 100 meV, and the reduction of the exciton–phonon coupling, caused by quantum confinement. For this statement, the synthesis of ZnO-based MQWs is necessary and important [6,7]. From the viewpoint of band-gap engineering, with respect to higher band gaps, an increase up to 4.0 eV has been achieved by the incorporation of magnesium into ZnO layers [8]. A narrowing of the band-gap is also desirable, to tune the emission wavelength of future optoelectronic devices into the visible. Ternary Zn1-xCdxO seems to be an appropriate candidate for this because of the smaller direct band-gap of CdO of 2.3 eV [9]. In addition, low magnesium concentrations of ZnMgO and ZnO, with hexagonal wurtzite structures, reduce the dislocation caused by a diminution in the lattice mismatch between them [10,11]. Therefore, the ZnO/ZnMgO QW structures have recently become a popular research topic [12,13]. The characterization of ZnO/ZnMgO QW can be controlled by the width of well, or the magnesium concentrations of ZnMgO layer [14,15]. For the higher magnesium concentrations of ZnO/ZnMgO QW, this has a stronger exciton confinement ability owing to the higher energy gap of ZnMgO barrier layer, and stronger quantum-confined Stark effect (QCSE) as a result of higher piezoelectric field generation in the QW structure. The electric field separates the electrons and holes present in the QW after excitation, reducing the overlap of their respective wave functions. The use of ZnO/ZnMgO quantum wells with graded barriers [16] had also been reported for achieving improved electron-hole wave function overlap for suppressing the charge separation in polar quantum wells, which are similar to the concept widely studied and demonstrated in the InGaN QWs with large overlap designs [1719]. A decrease in the exciton binding energy of ZnO-based QW heterostructures, and the emission efficiency ZnO-based QW devices, with magnesium concentrations, are observed [16,20]. Therefore, the study of suitable width of well and magnesium concentrations of the ZnMgO barrier layer in ZnO-based QW heterostructures is an important issue. In addition to the ZnO-based approach, significant advances have been reported for addressing high performance mid / deep UV sources by using AlGaN-based [2124] and AlInN-based [25,26] material systems.

ZnO films are usually grown on c-Al2O3 substrate owing to its cheap price, large wafer size, and availability for growing epitaxial films [27]. However, when ZnO films are grown directly on (0001) Al2O3 substrates without any buffer layer, the ZnO films generally show poor crystal quality, because of the 18% lattice mismatch between ZnO and Al2O3. To reduce lattice misfit and improve crystal quality, an MgO buffer layer has been suggested and applied successfully [2831].

In this paper, the growth of single and multiple ZnO/ZnMgO quantum wells samples on c-plane sapphire substrates by a two-step temperature variation growth of ZnO buffer layers was demonstrated, using two kinds of Mg concentrations of ZnMgO layer, and a MgO buffer layer for crystallinity improvement [32,33]. The calculations of Mg concentrations are from x-ray diffraction (XRD) and energy dispersive spectrometer (EDS) measurements. The crystallization quality and strain distribution of the samples were analyzed through XRD and x-ray rocking curve (XRC) measurements. Temperature-dependent photoluminescence results showed the ability of exciton confinement dependence on Mg concentrations, and the width of the barrier layer. Finally, the growth of ZnO/ZnMgO MQWs sample, based on the optimal barrier layer conditions, was shown. The MQW structure of the sample was proved by high-resolution transmission electron microscopy (HRTEM).

2. Growth conditions and structures of samples

The ZnO-based QW heterostructures were grown on commercial (0001) c-Al2O3 substrates by molecular beam epitaxy (MBE). For Sample A, a MgO buffer layer was grown with a thickness of 7 nm on the c-Al2O3 substrate. In this step, the growth temperature, the effusion cell temperature of Mg, and O2 flow rate were 550°C, 380°C, and 3 sccm, respectively. Then, a low-temperature growth ZnO (LT-ZnO) buffer layer was grown, with a thickness of 18 nm on the MgO buffer layer. In this step, the growth temperature, the effusion cell temperature of Zn, O2 flow rate, and thermal annealing were 300°C, 295°C, 3 sccm, and 700°C for 10 minutes, respectively. The HT-ZnO buffer layer was grown with a thickness of 100 nm on the LT-ZnO buffer layer. In this step, the growth temperature, the effusion cell temperature of Zn, and O2 flow rate were 600°C, 295°C, and 1 sccm, respectively. The Zn0.9Mg0.1O barrier layer was grown with a thickness of 100 nm on the HT-ZnO buffer layer. In this step, the growth temperature and O2 flow rate were 500°C and 2.85 sccm, respectively. The ZnO well layer was grown with a thickness of 2 nm on the Zn0.9Mg0.1O barrier layer. In this step, the growth temperature and beam equivalent pressure were 500°C and 1.6 × 10−6 torr, respectively. Finally, the Zn0.9Mg0.1O capping layer was grown with a thickness of 20 nm on the ZnO well layer. In this step, the growth conditions are the same as the Zn0.9Mg0.1O barrier layer. For Sample B, the differences compared with Sample A are a Mg concentration increase of 20% of both the ZnMgO barrier and capping layer, a thickness increase to 220 nm, and an O2 flow rate increase to 3.05 in the ZnMgO barrier layer. Sample A and Sample B is the single ZnO/ZnMgO QW sample. Sample C contains the three QWs structure, with the same growth conditions as Sample B. Sample D is the control sample with sapphire/MgO/LT-ZnO/HT-ZnO structure under the same growth conditions as the others. Figure 1 summarizes the layer structures of the samples.

 

Fig. 1 Schematic picture for the layer structures of (a) Sample A, (b) Sample B, (c) Sample C, and (d) Sample D, used in this work.

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3. XRD and XRC measurements

Figure 2(a) shows the XRD spectra of the samples, with a (0002) ZnMgO peak and a weak (200) MgO peak [34,35]. Figure 2(b) shows the normalized XRC results of the samples. Table 1 summarizes the material parameters of the samples obtained from XRD measurements. Following Ohtomo’s study [36], Mg concentration is inversely proportional to the lattice constant c. We can estimate the Mg concentration of Zn1-xMgxO. The 2 theta value of Sample A and B is 34.46° and 34.58°, respectively corresponding to the Mg concentration x is about 0.1 and 0.2. Through EDS measurement Mg / Zn atomic percentage were 0.242 and 0.303, the calculated Mg concentration x of the sample A and B was 0.195 and 0.233, but due to the influence of the existence of the buffer layer of MgO and ZnO in the EDS measurements, so the results are not exact values​​, but can be confirmed the Mg concentration trend estimate from XRD measurement is correct. In these results, 2 theta value of Sample B (34.58°) is larger than Sample A (34.46°), owing to Sample B having a higher Mg concentration of ZnMgO layer growth. For ZnMgO growth, the lattice is compressed by replacing Zn with Mg atom. The lattice compression results in the lattice constant c decrease and 2 theta value of ZnMgO materials increase [37]. For stress calculations, the stress in ZnMgO layer increases with the Mg concentration and thickness of ZnMgO layer. Therefore, Sample B has a larger stress of 2.04 Gpa than Sample A, 0.57 Gpa, owing to Sample B having a higher Mg concentration and thicker ZnMgO layer (220 nm) growth. The 220 nm thickness of the ZnMgO layer is below the critical thickness of that for high crystallinity growth processes [38]. For XRC measurements, the FWHM (full width at half maximum) of Sample A and B is 274.50 arcsec and 245.68 arcsec, respectively. The lower FWHM value (11% decreasing) shows completed and compacted growth of Sample B. For Sample B growth, higher Mg concentration results in more defects in the ZnMgO layer, but a thicker first ZnMgO barrier layer growth overcomes this problem.

 

Fig. 2 (a) XRD ω-2θ spectra, and (b) normalized XRC results of Samples A, B, C, and D.

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Tables Icon

Table 1. Peak Position, FWHM, Strain, Stress, Lattice Constant, EDS Mg/Zn Ratio, and Mg Concentrations of the Samples from XRD Measurements

Figure 3 shows the ideal band diagram of Samples A and B from calculations. The calculations of ZnO/ZnMgO QW band structure come from the combination between the energy band gap for Zn(1 − x)MgxO, which is taken as Eg = 3.37 + 2.51x, and the band offsets, which are, Ec/Ev = 9 [10,39]. For Sample A, the Mg concentration is 0.1 (x = 0.1) responses to 3.621 eV energy gap of Zn0.9Mg0.1O. The band offset is 0.9 responses to 225.9 meV conduction band offset, and 25.1 meV valence band offset. For Sample B, the Mg concentration is 0.2 (x = 0.2) responses to 3.872 eV energy gap of Zn0.8Mg0.2O, 431.8 meV conduction band offset, and 50.2 meV valence band offset.

 

Fig. 3 Band diagram of (a) Sample A, and (b) Sample B.

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In comparison with Sample A, Sample B with a higher barrier energy, results in a deeper QW structure and stronger exciton confinement ability. In comparison with Sample A, and B, Sample C with MQWs growth, shows some reasonable results at about intermediate 2 theta value, stress value, and narrow FWHM of XRC. Sample D, the control sample, presented all samples growth on the same buffer layers with stress-free, high quality, and low defects [33].

4. Temperature-dependent PL measurements

Figure 4 shows the PL spectra of Samples A, B, C, and D with a 325 nm HeCd laser excitation at 10 K. The exciton emission energy of Samples A, B, C, and D is 3.3926, 3.4216, 3.4425, and 3.3686 eV, respectively. Compared with Sample D, the exciton emission energies show blueshift of about 28.05, 53.07, and 73.97 eV of Samples A, B, and, C. The exciton emission energy of samples increased with the Mg concentration of ZnMgO barrier layer, owing to exciton confinement effect enhancement [40]. In this study, Samples B and C have a higher exciton confinement ability for higher Mg concentrations. At the lower exciton emission energy side region, two weak peaks were found, which presented acceptor-bound exciton and Lo-phonon replicas contributions [39,4143]. The barrier layer (Zn(1 − x)MgxO) emission energy of Samples A, B, and C is 3.6752, 3.5838, and 3.5924 eV, respectively. Form theory calculation, the higher Mg concentration of ZnMgO barrier layer resulted in the larger emission energy [10,39]. Here, the barrier layer emission energies of Samples B and C show redshift rather than theory calculation above. These differences come from the band-gap tilt of the barrier, resulting from the higher stress existence in the thicker barrier growth conditions of Samples B and C. This redshift of barrier energy was also shown in Matsui’s report [44]. The phase separation in ZnMgO buffer layer occurred as the layer thick than critical thickness of ZnMgO [44]. The barrier emission energies of Samples B and C indicated that the relaxed layers were comprised of two phases, Mg-rich and Mg-poor regions, giving rise to band-edge emissions at 3.5838, 3.5514 eV (Mg-rich and Mg-poor of Sample B) and 3.5924, 3.5705 eV (Mg-rich and Mg-poor of Sample C), respectively [44]. Similar results have been reported for the InxGa1−xN/GaN system where Shimizu et al. observed double peak bandedge emissions from relaxed In0.19Ga0.81N layer covered with 3D islands and considered that the sample included In-rich quantum dots or phase-separated regions [45,46]. The lateral size of the nanodots was in the order of 100–200 nm. These are unable to form quantum dots since the Bohr radius of the excitons in ZnO is ca. 1.8 nm. Sugahara et al. reported that screw dislocations relating to spiral growth of hexagonal hillocks on InGaN surfaces were completely separated to In-rich and In-poor InGaN layers [47].

 

Fig. 4 PL spectra of samples at 10 K.

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Figures 5(a) , 5(b), and 5(c) show the temperature-dependent PL measurements of Samples A, B, and C, respectively. In Fig. 5(a), two emission peaks were found. The higher and lower energy peaks corresponded to the free excitons (blue points) and localized excitons (red points) emission. Both peaks show redshift with temperature which is the contribution of band-gap shrinkage. In Fig. 5(b), the QW emission of Sample B shows a broader peak (green points), with the free exciton and localized exciton emission peaks merging into that. The higher quantum confinement ability can localize more excitons, resulting in broader emission peaks and tail states tilt of Sample B. These emission peaks show an S-shape variation with temperature, indicating the existence of two possible explanations. The first is caused by a change in the exciton dynamics with temperature, owing to inhomogeneity and the exciton localization effect [48]. For a lower temperature range, the relatively long relaxation time of excitons gives the excitons more opportunity to relax down into lower energy tail states, caused by the inhomogeneous potential fluctuations, before recombining. This behavior produces a redshift in the peak energy position with increasing temperature. For T > 50 K, the exciton lifetimes decrease with increasing temperature. Thus, these excitons recombine before reaching the lower energy tail states. This behavior enhances a broadening of the higher-energy side emission, and leads to a blueshift in the peak energy. For T > 200 K, a redshift appears again with band-gap shrinkage [48]. The second is caused by a change in the exciton dynamics with temperature, owing to donor-bound, acceptor-bound, and free excitons transformation [43].

 

Fig. 5 PL spectra as a function of temperatures of (a) Sample A, (b) Sample B, and (c) Sample C.

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For further discussion of the temperature-dependence exciton dynamics of Sample B, PL spectra deconvolution with Gaussian functions at 10 and 75 K are shown in Fig. 6 . The solid blue and red lines are PL spectrum of Sample B at 10 and 75 K, respectively. The dashed blue and red lines are curve fitting results of two contributions from localized excitons and free excitons. Both localized excitons and free excitons emissions were measured at 10 K. Dominant free exciton emission at a low temperature (10 K) was observed by photoluminescence spectroscopy. It was attributed to the enhancement of the free exciton emission, induced by the high crystalline quality of the QW [49]. When temperature increased to 75 K, the localized excitons had more thermal energy to become free excitons. This excitons dynamics for localized excitons contribution decrease resulted in blueshift in the peak energy position, with temperatures from 75 K to 170 K. For T > 170 K, the localized excitons contribution was eliminated and the band-gap shrinkage can be considered. Then the redshift of peak energy position with temperature was found. In Fig. 5(c), the S-shape variation of peak energy position cannot be found, owing to the broaden emission peak by three QWs structure of Sample C. In order to compare the optical quality of these samples, the normalized integrated intensity of PL, as a function of temperature for each of the samples, is shown in Fig. 7 . The integrated intensity ranges from 3.35 eV to 3.48 eV, corresponding to the ZnO QW emission range of samples in Fig. 5. The normalized integrated intensity means the integrated intensity of each temperature is divided by integrated intensity at 10 K for each of the samples. For Sample B, the higher exciton confinement ability decreased the nonradiative recombination at higher temperatures. For Sample C, more quantum confinement with higher barrier energy was investigated by observing the blueshift of PL peaks at the low temperatures. The MQWs structure increased the exciton confinement ability to enhance the light emission efficiency of the sample. From the above description, one can see that the order of ZnO QW (MQWs) optical quality, from best to worst, is C, B, and A.

 

Fig. 6 PL spectra of Sample B, deconvoluted with Gaussian functions at 10 and 75K.

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Fig. 7 The normalized integrated intensity of samples as functions of temperature.

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5. HRTEM images of ZnO/ZnMgO MQWs

To understand the consistency between the optical measurements and structural measurements, cross-section HRTEM images were made. The HRTEM investigations were performed using a JEM-3000F field emission transmission electron microscope (FE-TEM), with an accelerating voltage of 300 kV, and a 0.14nm point resolution. Figure 8(a) shows the cross-section HRTEM image of Sample C. In this figure, the layer structure of Sample C was found clearly. In the MQWs part, it shows the wave-like structures of ZnO/ZnMgO layer. The wave-like structures were found in the early study owing to some material growth problems during ZnO/ZnMgO heterostructure growth [4]. Figure 8(b) shows the enlarged image from the blue dashed line region of wave-like structures in Fig. 8(a). From this image, the three ZnO/ZnMgO QWs were found. The MQWs structure was not clear as a result of the slight lattice constant change between ZnO and ZnMgO, caused by the lower Mg concentration condition. The variation in the QW widths also is found which it may influence the quantum confinement ability in samples. A possible reason to form “the wavy surface” is due to different atoms have different stacking direction in the epitaxial process, and then formed interleaved surface. It can show as a wavy structure in the macro-viewing. However, in the HRTEM image (Fig. 8(b)), it shows a jagged structure regularly. In the past, the presence of such a jagged structure may cause the defects in material growth processes and decreased the light emission. But in this study, we found the jagged structures result in light emitting peak widened and the light emitting efficiency increased as to the characteristics of the surface roughening of the device which it reduced the total reflection critical angle in the interfaces of the device. Figure 8(c) shows the enlarged image from the red dashed line region of (a). In this image, the formation of the spinel intermediate layer (MgOAl2O3) was found. An intermediate spinel layer, in epitaxial relation with the sapphire substrate, as well as with the MgO buffer layer, can reduce the ZnO overgrown with the sapphire substrate to reach the high quality ZnO thin film growth [50].

 

Fig. 8 (a) HRTEM image of Sample C, (b) Enlarged image of blue dashed line area in (a), and (c) Enlarged image of red dashed line area in (a).

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6. Conclusion

In conclusion, we investigated the influence of the Mg concentrations and ZnMgO barrier layer thickness on the structural, electrical, and optical properties of ZnO/ZnMgO QW and MQWs, grown on sapphire substrates by MBE. The XRD and XRCs investigations revealed that the thicker first ZnMgO barrier layer to participate in ZnO/ZnMgO QW growth eliminated the defects leading to high crystallinity growth. The temperature-dependent PL revealed a strong exciton confinement with an S-shape variation of peak energy position, suggesting the good optical quality of the ZnO/ZnMgO QW sample. For Samples A, B and Sample C, an increase in the normalized integrated intensity of PL at higher temperatures demonstrated the enhancement of the material and optical qualities of the ZnO/ZnMgO MQWs sample. For transmission electron microscopy (TEM) study, the three QW structures of Sample C were clearly seen. The MQWs structure of ZnO/ZnMgO increased the light emission efficiency, and screened the S-shape variation of the PL peak position of the sample.

Acknowledgments

This research was supported by the National Science Council, The Republic of China, under the Grants NSC 99-2622-E-002-022-CC2, 99-2221-E-002-123-MY3, 99-2221-E-002-113, 100-2221-E-194-043, 101-2221-E-194-049, 99-2112-M-390-002-MY3, and 99-2221-E-194-007-MY2, and the US Air Force Scientific Research Office, under the contract AOARD-10-4049.

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33. S. Y. Ting, P. J. Chen, H. C. Wang, C. H. Liao, W. M. Chang, Y. P. Hsieh, and C. C. Yang, “Crystallinity improvement of ZnO thin film on different buffer layers grown by MBE,” J. Nanomater. 2012, 6 (2012), doi:. [CrossRef]  

34. K. Koike, G. Y. Takada, K. Fujimoto, S. Sasa, M. Inoue, and M. Yano, “Characterization of [ZnO]m[ZnMgO]n multiple quantum wells grown by molecular beam epitaxy,” Physica E 32(1-2), 191–194 (2006). [CrossRef]  

35. S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008). [CrossRef]  

36. A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998). [CrossRef]  

37. A. El-Shaer, A. Bakin, M. Al-Suleiman, S. Ivanov, A. Che Mofor, and A. Waag, “Growth of wide band gap wurtzite ZnMgO layers on (0001) Al2O3 by radical-source molecular beam epitaxy,” Superlattices Microstruct. 42(1-6), 129–133 (2007). [CrossRef]  

38. H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006). [CrossRef]  

39. K. Koike, I. Nakashima, K. Hashimoto, S. Sasa, M. Inoue, and M. Yano, “Characteristics of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor grown on sapphire substrate by molecular-beam epitaxy,” Appl. Phys. Lett. 87(11), 112106 (2005). [CrossRef]  

40. T. Gruber, C. Kirchner, R. Kling, F. Reuss, and A. Waag, “ZnMgO epilayers and ZnO-ZnMgO quantum wells for optoelectronic applications in the blue and UV spectral region,” Appl. Phys. Lett. 84(26), 5359–5361 (2004). [CrossRef]  

41. T. Makino, K. Tamura, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, and H. Koinuma, “Effect of MgZnO-layer capping on optical properties of ZnO epitaxial layers,” Appl. Phys. Lett. 81(12), 2172–2174 (2002). [CrossRef]  

42. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Phonon replicas in ZnO/ZnMgO multiquantum wells,” J. Appl. Phys. 91(10), 6457–6460 (2002). [CrossRef]  

43. Y. Chen, F. Jiang, L. Wang, C. Zheng, J. Dai, Y. Pu, and W. Fang, “Structural and luminescent properties of ZnO epitaxial film grown on Si(111) substrate by atmospheric-pressure MOCVD,” J. Cryst. Growth 275(3-4), 486–491 (2005). [CrossRef]  

44. H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006). [CrossRef]  

45. M. Shimizu, Y. Kawaguchi, K. Hiramatsu, and N. Sawaki, “Metalorganic vapor phase epitaxy of thick InGaN on sapphire substrate,” Jpn. J. Appl. Phys. Part 1 36(Part 1, No. 6A), 3381–3384 (1997). [CrossRef]  

46. S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002). [CrossRef]  

47. T. Sugahara, M. Hao, T. Wang, D. Nakagawa, Y. Naoi, K. Nishino, and S. Sakai, “Role of dislocation in InGaN phase separation,” Jpn. J. Appl. Phys. Part 2 37(Part 2, No. 10B), L1195–L1198 (1998). [CrossRef]  

48. T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001). [CrossRef]  

49. K. Wu, H. He, Y. Lu, J. Huang, and Z. Ye, “Dominant free exciton emission in ZnO nanorods,” Nanoscale 4(5), 1701–1706 (2012). [CrossRef]   [PubMed]  

50. A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007). [CrossRef]  

References

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  17. R. A. Arif, Y.-K. Ee, and N. Tansu, “Polarization engineering via staggered InGaN quantum wells for radiative efficiency enhancement of light emitting diodes,” Appl. Phys. Lett. 91(9), 091110 (2007).
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  22. J. Zhang, H. Zhao, and N. Tansu, “Large optical gain AlGaN-delta-GaN quantum wells laser active regions in mid- and deep-ultraviolet spectral regimes,” Appl. Phys. Lett. 98(17), 171111 (2011).
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    [Crossref]
  26. R. B. Chung, F. Wu, R. Shivaraman, S. Keller, S. P. DenBaars, J. S. Speck, and S. Nakamura, “Growth study and ipurity characterization of AlxIn1−xN grown by metal organic chemical vapor deposition,” J. Cryst. Growth 324(1), 163–167 (2011).
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  28. A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
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  29. Y. Chen, H. J. Ko, S. K. Hong, and T. Yao, “Layer-by-layer growth of ZnO epilayer on Al2O3 (0001) by using a MgO buffer layer,” Appl. Phys. Lett. 76(5), 559–561 (2000).
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  32. Y. J. Chen, Y. Y. Shih, C. H. Ho, J. H. Du, and Y. P. Fu, “Effect of temperature on lateral growth of ZnO grains grown by MOCVD,” Ceram. Int. 36(1), 69–73 (2010).
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  33. S. Y. Ting, P. J. Chen, H. C. Wang, C. H. Liao, W. M. Chang, Y. P. Hsieh, and C. C. Yang, “Crystallinity improvement of ZnO thin film on different buffer layers grown by MBE,” J. Nanomater. 2012, 6 (2012), doi:.
    [Crossref]
  34. K. Koike, G. Y. Takada, K. Fujimoto, S. Sasa, M. Inoue, and M. Yano, “Characterization of [ZnO]m[ZnMgO]n multiple quantum wells grown by molecular beam epitaxy,” Physica E 32(1-2), 191–194 (2006).
    [Crossref]
  35. S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008).
    [Crossref]
  36. A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
    [Crossref]
  37. A. El-Shaer, A. Bakin, M. Al-Suleiman, S. Ivanov, A. Che Mofor, and A. Waag, “Growth of wide band gap wurtzite ZnMgO layers on (0001) Al2O3 by radical-source molecular beam epitaxy,” Superlattices Microstruct. 42(1-6), 129–133 (2007).
    [Crossref]
  38. H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
    [Crossref]
  39. K. Koike, I. Nakashima, K. Hashimoto, S. Sasa, M. Inoue, and M. Yano, “Characteristics of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor grown on sapphire substrate by molecular-beam epitaxy,” Appl. Phys. Lett. 87(11), 112106 (2005).
    [Crossref]
  40. T. Gruber, C. Kirchner, R. Kling, F. Reuss, and A. Waag, “ZnMgO epilayers and ZnO-ZnMgO quantum wells for optoelectronic applications in the blue and UV spectral region,” Appl. Phys. Lett. 84(26), 5359–5361 (2004).
    [Crossref]
  41. T. Makino, K. Tamura, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, and H. Koinuma, “Effect of MgZnO-layer capping on optical properties of ZnO epitaxial layers,” Appl. Phys. Lett. 81(12), 2172–2174 (2002).
    [Crossref]
  42. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Phonon replicas in ZnO/ZnMgO multiquantum wells,” J. Appl. Phys. 91(10), 6457–6460 (2002).
    [Crossref]
  43. Y. Chen, F. Jiang, L. Wang, C. Zheng, J. Dai, Y. Pu, and W. Fang, “Structural and luminescent properties of ZnO epitaxial film grown on Si(111) substrate by atmospheric-pressure MOCVD,” J. Cryst. Growth 275(3-4), 486–491 (2005).
    [Crossref]
  44. H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
    [Crossref]
  45. M. Shimizu, Y. Kawaguchi, K. Hiramatsu, and N. Sawaki, “Metalorganic vapor phase epitaxy of thick InGaN on sapphire substrate,” Jpn. J. Appl. Phys. Part 1 36(Part 1, No. 6A), 3381–3384 (1997).
    [Crossref]
  46. S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
    [Crossref]
  47. T. Sugahara, M. Hao, T. Wang, D. Nakagawa, Y. Naoi, K. Nishino, and S. Sakai, “Role of dislocation in InGaN phase separation,” Jpn. J. Appl. Phys. Part 2 37(Part 2, No. 10B), L1195–L1198 (1998).
    [Crossref]
  48. T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
    [Crossref]
  49. K. Wu, H. He, Y. Lu, J. Huang, and Z. Ye, “Dominant free exciton emission in ZnO nanorods,” Nanoscale 4(5), 1701–1706 (2012).
    [Crossref] [PubMed]
  50. A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
    [Crossref]

2012 (5)

R. Thierry, G. Perillat-Merceroz, P. H. Jouneau, P. Ferret, and G. Feuillet, “Core-shell multi-quantum wells in ZnO/ZnMgO nanowires with high optical efficiency at room temperature,” Nanotechnology 23(8), 085705 (2012).
[Crossref] [PubMed]

E. Francesco Pecora, W. Zhang, A. Yu. Nikiforov, L. Zhou, D. J. Smith, J. Yin, R. Paiella, L. Dal Negro, and T. D. Moustakas, “Sub-250 nm room-temperature optical gain from AlGaN/AlN multiple quantum wells with strong band-structure potential fluctuations,” Appl. Phys. Lett. 100(6), 061111 (2012).
[Crossref]

G. Liu, J. Zhang, X. H. Li, G. S. Huang, T. Paskova, K. R. Evans, H. Zhao, and N. Tansu, “Metalorganic vapor phase epitaxy and characterizations of nearly-lattice-matched AlInN alloys on GaN/sapphire templates and free-standing GaN substrates,” J. Cryst. Growth 340(1), 66–73 (2012).
[Crossref]

S. Y. Ting, P. J. Chen, H. C. Wang, C. H. Liao, W. M. Chang, Y. P. Hsieh, and C. C. Yang, “Crystallinity improvement of ZnO thin film on different buffer layers grown by MBE,” J. Nanomater. 2012, 6 (2012), doi:.
[Crossref]

K. Wu, H. He, Y. Lu, J. Huang, and Z. Ye, “Dominant free exciton emission in ZnO nanorods,” Nanoscale 4(5), 1701–1706 (2012).
[Crossref] [PubMed]

2011 (6)

R. B. Chung, F. Wu, R. Shivaraman, S. Keller, S. P. DenBaars, J. S. Speck, and S. Nakamura, “Growth study and ipurity characterization of AlxIn1−xN grown by metal organic chemical vapor deposition,” J. Cryst. Growth 324(1), 163–167 (2011).
[Crossref]

H. P. Zhao, G. Y. Liu, J. Zhang, J. D. Poplawsky, V. Dierolf, and N. Tansu, “Approaches for high internal quantum efficiency green InGaN light-emitting diodes with large overlap quantum wells,” Opt. Express 19(S4Suppl 4), A991–A1007 (2011).
[Crossref] [PubMed]

J. Zhang, H. Zhao, and N. Tansu, “Large optical gain AlGaN-delta-GaN quantum wells laser active regions in mid- and deep-ultraviolet spectral regimes,” Appl. Phys. Lett. 98(17), 171111 (2011).
[Crossref]

Y. Taniyasu and M. Kasu, “Polarization property of deep-ultraviolet light emission from C-plane AlN/GaN short-period superlattices,” Appl. Phys. Lett. 99(25), 251112 (2011).
[Crossref]

M. Brandt, H. Wenckstern, M. Stölzel, H. Hochmuth, M. Lorenz, and M. Grundmann, “Semiconducting oxide heterostructures,” Semicond. Sci. Technol. 26(1), 014040 (2011).
[Crossref]

H. Long, G. Fang, S. Li, X. Mo, H. Wang, H. Huang, Q. Jiang, J. Wang, and X. Zhao, “A ZnO/ZnMgO multiple-quantum-well ultraviolet random laser diode,” IEEE Electron Device Lett. 32(1), 54–56 (2011).
[Crossref]

2010 (5)

C. R. Hall, L. V. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, C. Jagadish, and J. A. Davis, “Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field,” Appl. Phys. Lett. 96(19), 193117 (2010).
[Crossref]

M. Brandt, M. Lange, M. Stölzel, A. Müller, G. Benndorf, J. Zippel, J. Lenzner, M. Lorenz, and M. Grundmann, “Control of interface abruptness of polar MgZnO/ZnO quantum wells grown by pulsed laser deposition,” Appl. Phys. Lett. 97(5), 052101 (2010).
[Crossref]

J. Zhang, H. Zhao, and N. Tansu, “Effect of crystal-field split-off hole and heavy-hole bands crossover on gain characteristics of high Al-content AlGaN quantum well lasers,” Appl. Phys. Lett. 97(11), 111105 (2010).
[Crossref]

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

Y. J. Chen, Y. Y. Shih, C. H. Ho, J. H. Du, and Y. P. Fu, “Effect of temperature on lateral growth of ZnO grains grown by MOCVD,” Ceram. Int. 36(1), 69–73 (2010).
[Crossref]

2009 (1)

H. P. Zhao, G. Y. Liu, X. H. Li, R. A. Arif, G. S. Huang, J. D. Poplawsky, S. Tafon Penn, V. Dierolf, and N. Tansu, “Design and characteristics of staggered InGaN quantum well light-emitting diodes in the green spectral regimes,” IET Optoelectron. 3(6), 283–295 (2009).
[Crossref]

2008 (1)

S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008).
[Crossref]

2007 (5)

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

R. A. Arif, Y.-K. Ee, and N. Tansu, “Polarization engineering via staggered InGaN quantum wells for radiative efficiency enhancement of light emitting diodes,” Appl. Phys. Lett. 91(9), 091110 (2007).
[Crossref]

X. Q. Gu, L. P. Zhu, Z. Z. Ye, H. P. He, Y. Z. Zhang, F. Huang, M. X. Qiu, Y. J. Zeng, F. Liu, and W. Jaeger, “Room-temperature photoluminescence from ZnO/ZnMgO multiple quantum wells grown on Si(111) substrates,” Appl. Phys. Lett. 91(2), 022103 (2007).
[Crossref]

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

A. El-Shaer, A. Bakin, M. Al-Suleiman, S. Ivanov, A. Che Mofor, and A. Waag, “Growth of wide band gap wurtzite ZnMgO layers on (0001) Al2O3 by radical-source molecular beam epitaxy,” Superlattices Microstruct. 42(1-6), 129–133 (2007).
[Crossref]

2006 (5)

H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
[Crossref]

K. Koike, G. Y. Takada, K. Fujimoto, S. Sasa, M. Inoue, and M. Yano, “Characterization of [ZnO]m[ZnMgO]n multiple quantum wells grown by molecular beam epitaxy,” Physica E 32(1-2), 191–194 (2006).
[Crossref]

V. A. Coleman, M. Buda, H. H. Tan, C. Jagadish, M. R. Phillips, K. Koike, S. Sasa, M. Inoue, and M. Yano, “Observation of blue shifts in ZnO/ZnMgO multiple quantum well structures by ion-implantation induced intermixing,” Semicond. Sci. Technol. 21(3), L25–L28 (2006).
[Crossref]

J. H. Lim, C. K. Kang, K. K. Kim, I. K. Park, D. K. Hwang, and S. J. Park, “UV electroluminescence emission from ZnO light-emitting diodes grown by high-temperature radiofrequency sputtering,” Adv. Mater.  18(20), 2720–2724 (2006).
[Crossref]

H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
[Crossref]

2005 (4)

Y. Chen, F. Jiang, L. Wang, C. Zheng, J. Dai, Y. Pu, and W. Fang, “Structural and luminescent properties of ZnO epitaxial film grown on Si(111) substrate by atmospheric-pressure MOCVD,” J. Cryst. Growth 275(3-4), 486–491 (2005).
[Crossref]

T. Makino, Y. Segawa, M. Kawasaki, and H. Koinuma, “Optical properties of excitons in ZnO-based quantum well heterostructures,” Semicond. Sci. Technol. 20(4), S78–S91 (2005).
[Crossref]

T. Makino, Y. Segawa, and M. Kawasaki, “Analytical study on exciton - longitudinal - optical - phonon coupling and comparison with experiment for ZnO quantum wells,” J. Appl. Phys. 97(10), 106111 (2005).
[Crossref]

K. Koike, I. Nakashima, K. Hashimoto, S. Sasa, M. Inoue, and M. Yano, “Characteristics of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor grown on sapphire substrate by molecular-beam epitaxy,” Appl. Phys. Lett. 87(11), 112106 (2005).
[Crossref]

2004 (2)

T. Gruber, C. Kirchner, R. Kling, F. Reuss, and A. Waag, “ZnMgO epilayers and ZnO-ZnMgO quantum wells for optoelectronic applications in the blue and UV spectral region,” Appl. Phys. Lett. 84(26), 5359–5361 (2004).
[Crossref]

H. Kato, K. Miyamoto, M. Sano, and T. Yao, “Polarity control of ZnO on sapphire by varying the MgO buffer layer thickness,” Appl. Phys. Lett. 84(22), 4562–4564 (2004).
[Crossref]

2003 (1)

T. Gruber, C. Kirchner, R. Kling, F. Reuss, A. Waag, F. Bertram, D. Forster, J. Christen, and M. Schreck, “Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy,” Appl. Phys. Lett. 83(16), 3290–3292 (2003).
[Crossref]

2002 (3)

T. Makino, K. Tamura, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, and H. Koinuma, “Effect of MgZnO-layer capping on optical properties of ZnO epitaxial layers,” Appl. Phys. Lett. 81(12), 2172–2174 (2002).
[Crossref]

D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Phonon replicas in ZnO/ZnMgO multiquantum wells,” J. Appl. Phys. 91(10), 6457–6460 (2002).
[Crossref]

S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
[Crossref]

2001 (6)

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

Y. Chen, S. K. Hong, H. J. Ko, V. Kirshner, H. Wenisch, T. Yao, K. Inaba, and Y. Segawa, “Effects of an extremely thin buffer on heteroepitaxy with large lattice mismatch,” Appl. Phys. Lett. 78(21), 3352–3354 (2001).
[Crossref]

D. C. Look, “Recent advances in ZnO materials and devices,” Mater. Sci. Eng. B 80(1-3), 383–387 (2001).
[Crossref]

G. Coli and K. K. Bajaj, “Excitonic transitions in ZnO/MgZnO quantum well heterostructures,” Appl. Phys. Lett. 78(19), 2861–2863 (2001).
[Crossref]

T. Makino, Y. Segawa, M. Kawasaki, A. Ohtomo, R. Shiroki, K. Tamura, T. Yasuda, and H. Koinuma, “Band gap engineering based on MgxZn1−xO and CdyZn1−yO ternary alloy films,” Appl. Phys. Lett. 78(9), 1237–1239 (2001).
[Crossref]

W. I. Park, G. C. Yi, and H. M. Jang, “Metalorganic vapor-phase epitaxial growth and photoluminescent properties of Zn1−xMgxO(0 ≤ x ≤ 0.49) thin films,” Appl. Phys. Lett. 79(13), 2022–2024 (2001).
[Crossref]

2000 (2)

T. Makino, C. H. Chia, N. T. Tuan, H. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Room-temperature luminescence of excitons in ZnO/(Mg,Zn) O multiple quantum wells on lattice-matched substrates,” Appl. Phys. Lett. 77(7), 975–977 (2000).
[Crossref]

Y. Chen, H. J. Ko, S. K. Hong, and T. Yao, “Layer-by-layer growth of ZnO epilayer on Al2O3 (0001) by using a MgO buffer layer,” Appl. Phys. Lett. 76(5), 559–561 (2000).
[Crossref]

1998 (2)

T. Sugahara, M. Hao, T. Wang, D. Nakagawa, Y. Naoi, K. Nishino, and S. Sakai, “Role of dislocation in InGaN phase separation,” Jpn. J. Appl. Phys. Part 2 37(Part 2, No. 10B), L1195–L1198 (1998).
[Crossref]

A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
[Crossref]

1997 (2)

M. Shimizu, Y. Kawaguchi, K. Hiramatsu, and N. Sawaki, “Metalorganic vapor phase epitaxy of thick InGaN on sapphire substrate,” Jpn. J. Appl. Phys. Part 1 36(Part 1, No. 6A), 3381–3384 (1997).
[Crossref]

D. M. Bagnall, Y. F. Chen, Z. Zhu, T. Yao, S. Koyama, M. Y. Shen, and T. Goto, “Optically pumped lasing of ZnO at room temperature,” Appl. Phys. Lett. 70(17), 2230–2232 (1997).
[Crossref]

Akiyama, H.

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

Al-Suleiman, M.

A. El-Shaer, A. Bakin, M. Al-Suleiman, S. Ivanov, A. Che Mofor, and A. Waag, “Growth of wide band gap wurtzite ZnMgO layers on (0001) Al2O3 by radical-source molecular beam epitaxy,” Superlattices Microstruct. 42(1-6), 129–133 (2007).
[Crossref]

Alves, E.

S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
[Crossref]

Arif, R. A.

H. P. Zhao, G. Y. Liu, X. H. Li, R. A. Arif, G. S. Huang, J. D. Poplawsky, S. Tafon Penn, V. Dierolf, and N. Tansu, “Design and characteristics of staggered InGaN quantum well light-emitting diodes in the green spectral regimes,” IET Optoelectron. 3(6), 283–295 (2009).
[Crossref]

R. A. Arif, Y.-K. Ee, and N. Tansu, “Polarization engineering via staggered InGaN quantum wells for radiative efficiency enhancement of light emitting diodes,” Appl. Phys. Lett. 91(9), 091110 (2007).
[Crossref]

Baba, M.

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

Bagnall, D. M.

D. M. Bagnall, Y. F. Chen, Z. Zhu, T. Yao, S. Koyama, M. Y. Shen, and T. Goto, “Optically pumped lasing of ZnO at room temperature,” Appl. Phys. Lett. 70(17), 2230–2232 (1997).
[Crossref]

Bajaj, K. K.

G. Coli and K. K. Bajaj, “Excitonic transitions in ZnO/MgZnO quantum well heterostructures,” Appl. Phys. Lett. 78(19), 2861–2863 (2001).
[Crossref]

Bakin, A.

A. El-Shaer, A. Bakin, M. Al-Suleiman, S. Ivanov, A. Che Mofor, and A. Waag, “Growth of wide band gap wurtzite ZnMgO layers on (0001) Al2O3 by radical-source molecular beam epitaxy,” Superlattices Microstruct. 42(1-6), 129–133 (2007).
[Crossref]

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

Benndorf, G.

M. Brandt, M. Lange, M. Stölzel, A. Müller, G. Benndorf, J. Zippel, J. Lenzner, M. Lorenz, and M. Grundmann, “Control of interface abruptness of polar MgZnO/ZnO quantum wells grown by pulsed laser deposition,” Appl. Phys. Lett. 97(5), 052101 (2010).
[Crossref]

Bertram, F.

T. Gruber, C. Kirchner, R. Kling, F. Reuss, A. Waag, F. Bertram, D. Forster, J. Christen, and M. Schreck, “Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy,” Appl. Phys. Lett. 83(16), 3290–3292 (2003).
[Crossref]

Brandt, M.

M. Brandt, H. Wenckstern, M. Stölzel, H. Hochmuth, M. Lorenz, and M. Grundmann, “Semiconducting oxide heterostructures,” Semicond. Sci. Technol. 26(1), 014040 (2011).
[Crossref]

M. Brandt, M. Lange, M. Stölzel, A. Müller, G. Benndorf, J. Zippel, J. Lenzner, M. Lorenz, and M. Grundmann, “Control of interface abruptness of polar MgZnO/ZnO quantum wells grown by pulsed laser deposition,” Appl. Phys. Lett. 97(5), 052101 (2010).
[Crossref]

Buda, M.

V. A. Coleman, M. Buda, H. H. Tan, C. Jagadish, M. R. Phillips, K. Koike, S. Sasa, M. Inoue, and M. Yano, “Observation of blue shifts in ZnO/ZnMgO multiple quantum well structures by ion-implantation induced intermixing,” Semicond. Sci. Technol. 21(3), L25–L28 (2006).
[Crossref]

Chang, W. M.

S. Y. Ting, P. J. Chen, H. C. Wang, C. H. Liao, W. M. Chang, Y. P. Hsieh, and C. C. Yang, “Crystallinity improvement of ZnO thin film on different buffer layers grown by MBE,” J. Nanomater. 2012, 6 (2012), doi:.
[Crossref]

Che Mofor, A.

A. El-Shaer, A. Bakin, M. Al-Suleiman, S. Ivanov, A. Che Mofor, and A. Waag, “Growth of wide band gap wurtzite ZnMgO layers on (0001) Al2O3 by radical-source molecular beam epitaxy,” Superlattices Microstruct. 42(1-6), 129–133 (2007).
[Crossref]

Chen, P. J.

S. Y. Ting, P. J. Chen, H. C. Wang, C. H. Liao, W. M. Chang, Y. P. Hsieh, and C. C. Yang, “Crystallinity improvement of ZnO thin film on different buffer layers grown by MBE,” J. Nanomater. 2012, 6 (2012), doi:.
[Crossref]

Chen, Y.

Y. Chen, F. Jiang, L. Wang, C. Zheng, J. Dai, Y. Pu, and W. Fang, “Structural and luminescent properties of ZnO epitaxial film grown on Si(111) substrate by atmospheric-pressure MOCVD,” J. Cryst. Growth 275(3-4), 486–491 (2005).
[Crossref]

Y. Chen, S. K. Hong, H. J. Ko, V. Kirshner, H. Wenisch, T. Yao, K. Inaba, and Y. Segawa, “Effects of an extremely thin buffer on heteroepitaxy with large lattice mismatch,” Appl. Phys. Lett. 78(21), 3352–3354 (2001).
[Crossref]

Y. Chen, H. J. Ko, S. K. Hong, and T. Yao, “Layer-by-layer growth of ZnO epilayer on Al2O3 (0001) by using a MgO buffer layer,” Appl. Phys. Lett. 76(5), 559–561 (2000).
[Crossref]

Chen, Y. F.

D. M. Bagnall, Y. F. Chen, Z. Zhu, T. Yao, S. Koyama, M. Y. Shen, and T. Goto, “Optically pumped lasing of ZnO at room temperature,” Appl. Phys. Lett. 70(17), 2230–2232 (1997).
[Crossref]

Chen, Y. J.

Y. J. Chen, Y. Y. Shih, C. H. Ho, J. H. Du, and Y. P. Fu, “Effect of temperature on lateral growth of ZnO grains grown by MOCVD,” Ceram. Int. 36(1), 69–73 (2010).
[Crossref]

Chia, C. H.

T. Makino, K. Tamura, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, and H. Koinuma, “Effect of MgZnO-layer capping on optical properties of ZnO epitaxial layers,” Appl. Phys. Lett. 81(12), 2172–2174 (2002).
[Crossref]

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

T. Makino, C. H. Chia, N. T. Tuan, H. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Room-temperature luminescence of excitons in ZnO/(Mg,Zn) O multiple quantum wells on lattice-matched substrates,” Appl. Phys. Lett. 77(7), 975–977 (2000).
[Crossref]

Christen, J.

T. Gruber, C. Kirchner, R. Kling, F. Reuss, A. Waag, F. Bertram, D. Forster, J. Christen, and M. Schreck, “Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy,” Appl. Phys. Lett. 83(16), 3290–3292 (2003).
[Crossref]

Chung, R. B.

R. B. Chung, F. Wu, R. Shivaraman, S. Keller, S. P. DenBaars, J. S. Speck, and S. Nakamura, “Growth study and ipurity characterization of AlxIn1−xN grown by metal organic chemical vapor deposition,” J. Cryst. Growth 324(1), 163–167 (2011).
[Crossref]

Coleman, V. A.

V. A. Coleman, M. Buda, H. H. Tan, C. Jagadish, M. R. Phillips, K. Koike, S. Sasa, M. Inoue, and M. Yano, “Observation of blue shifts in ZnO/ZnMgO multiple quantum well structures by ion-implantation induced intermixing,” Semicond. Sci. Technol. 21(3), L25–L28 (2006).
[Crossref]

Coli, G.

G. Coli and K. K. Bajaj, “Excitonic transitions in ZnO/MgZnO quantum well heterostructures,” Appl. Phys. Lett. 78(19), 2861–2863 (2001).
[Crossref]

Correia, M. R.

S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
[Crossref]

Dai, J.

Y. Chen, F. Jiang, L. Wang, C. Zheng, J. Dai, Y. Pu, and W. Fang, “Structural and luminescent properties of ZnO epitaxial film grown on Si(111) substrate by atmospheric-pressure MOCVD,” J. Cryst. Growth 275(3-4), 486–491 (2005).
[Crossref]

Dal Negro, L.

E. Francesco Pecora, W. Zhang, A. Yu. Nikiforov, L. Zhou, D. J. Smith, J. Yin, R. Paiella, L. Dal Negro, and T. D. Moustakas, “Sub-250 nm room-temperature optical gain from AlGaN/AlN multiple quantum wells with strong band-structure potential fluctuations,” Appl. Phys. Lett. 100(6), 061111 (2012).
[Crossref]

Dao, L. V.

C. R. Hall, L. V. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, C. Jagadish, and J. A. Davis, “Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field,” Appl. Phys. Lett. 96(19), 193117 (2010).
[Crossref]

Davis, J. A.

C. R. Hall, L. V. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, C. Jagadish, and J. A. Davis, “Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field,” Appl. Phys. Lett. 96(19), 193117 (2010).
[Crossref]

DenBaars, S. P.

R. B. Chung, F. Wu, R. Shivaraman, S. Keller, S. P. DenBaars, J. S. Speck, and S. Nakamura, “Growth study and ipurity characterization of AlxIn1−xN grown by metal organic chemical vapor deposition,” J. Cryst. Growth 324(1), 163–167 (2011).
[Crossref]

Dierolf, V.

H. P. Zhao, G. Y. Liu, J. Zhang, J. D. Poplawsky, V. Dierolf, and N. Tansu, “Approaches for high internal quantum efficiency green InGaN light-emitting diodes with large overlap quantum wells,” Opt. Express 19(S4Suppl 4), A991–A1007 (2011).
[Crossref] [PubMed]

H. P. Zhao, G. Y. Liu, X. H. Li, R. A. Arif, G. S. Huang, J. D. Poplawsky, S. Tafon Penn, V. Dierolf, and N. Tansu, “Design and characteristics of staggered InGaN quantum well light-emitting diodes in the green spectral regimes,” IET Optoelectron. 3(6), 283–295 (2009).
[Crossref]

Du, J. H.

Y. J. Chen, Y. Y. Shih, C. H. Ho, J. H. Du, and Y. P. Fu, “Effect of temperature on lateral growth of ZnO grains grown by MOCVD,” Ceram. Int. 36(1), 69–73 (2010).
[Crossref]

Ee, Y.-K.

R. A. Arif, Y.-K. Ee, and N. Tansu, “Polarization engineering via staggered InGaN quantum wells for radiative efficiency enhancement of light emitting diodes,” Appl. Phys. Lett. 91(9), 091110 (2007).
[Crossref]

Egelhoff, W. F.

S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008).
[Crossref]

El-Shaer, A.

A. El-Shaer, A. Bakin, M. Al-Suleiman, S. Ivanov, A. Che Mofor, and A. Waag, “Growth of wide band gap wurtzite ZnMgO layers on (0001) Al2O3 by radical-source molecular beam epitaxy,” Superlattices Microstruct. 42(1-6), 129–133 (2007).
[Crossref]

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

Evans, K. R.

G. Liu, J. Zhang, X. H. Li, G. S. Huang, T. Paskova, K. R. Evans, H. Zhao, and N. Tansu, “Metalorganic vapor phase epitaxy and characterizations of nearly-lattice-matched AlInN alloys on GaN/sapphire templates and free-standing GaN substrates,” J. Cryst. Growth 340(1), 66–73 (2012).
[Crossref]

Fang, G.

H. Long, G. Fang, S. Li, X. Mo, H. Wang, H. Huang, Q. Jiang, J. Wang, and X. Zhao, “A ZnO/ZnMgO multiple-quantum-well ultraviolet random laser diode,” IEEE Electron Device Lett. 32(1), 54–56 (2011).
[Crossref]

Fang, W.

Y. Chen, F. Jiang, L. Wang, C. Zheng, J. Dai, Y. Pu, and W. Fang, “Structural and luminescent properties of ZnO epitaxial film grown on Si(111) substrate by atmospheric-pressure MOCVD,” J. Cryst. Growth 275(3-4), 486–491 (2005).
[Crossref]

Ferret, P.

R. Thierry, G. Perillat-Merceroz, P. H. Jouneau, P. Ferret, and G. Feuillet, “Core-shell multi-quantum wells in ZnO/ZnMgO nanowires with high optical efficiency at room temperature,” Nanotechnology 23(8), 085705 (2012).
[Crossref] [PubMed]

Feuillet, G.

R. Thierry, G. Perillat-Merceroz, P. H. Jouneau, P. Ferret, and G. Feuillet, “Core-shell multi-quantum wells in ZnO/ZnMgO nanowires with high optical efficiency at room temperature,” Nanotechnology 23(8), 085705 (2012).
[Crossref] [PubMed]

Forster, D.

T. Gruber, C. Kirchner, R. Kling, F. Reuss, A. Waag, F. Bertram, D. Forster, J. Christen, and M. Schreck, “Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy,” Appl. Phys. Lett. 83(16), 3290–3292 (2003).
[Crossref]

Francesco Pecora, E.

E. Francesco Pecora, W. Zhang, A. Yu. Nikiforov, L. Zhou, D. J. Smith, J. Yin, R. Paiella, L. Dal Negro, and T. D. Moustakas, “Sub-250 nm room-temperature optical gain from AlGaN/AlN multiple quantum wells with strong band-structure potential fluctuations,” Appl. Phys. Lett. 100(6), 061111 (2012).
[Crossref]

Franco, N.

S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
[Crossref]

Fu, Y. P.

Y. J. Chen, Y. Y. Shih, C. H. Ho, J. H. Du, and Y. P. Fu, “Effect of temperature on lateral growth of ZnO grains grown by MOCVD,” Ceram. Int. 36(1), 69–73 (2010).
[Crossref]

Fujimoto, K.

K. Koike, G. Y. Takada, K. Fujimoto, S. Sasa, M. Inoue, and M. Yano, “Characterization of [ZnO]m[ZnMgO]n multiple quantum wells grown by molecular beam epitaxy,” Physica E 32(1-2), 191–194 (2006).
[Crossref]

Goto, T.

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T. Gruber, C. Kirchner, R. Kling, F. Reuss, A. Waag, F. Bertram, D. Forster, J. Christen, and M. Schreck, “Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy,” Appl. Phys. Lett. 83(16), 3290–3292 (2003).
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Hall, C. R.

C. R. Hall, L. V. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, C. Jagadish, and J. A. Davis, “Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field,” Appl. Phys. Lett. 96(19), 193117 (2010).
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J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
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H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
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K. Koike, I. Nakashima, K. Hashimoto, S. Sasa, M. Inoue, and M. Yano, “Characteristics of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor grown on sapphire substrate by molecular-beam epitaxy,” Appl. Phys. Lett. 87(11), 112106 (2005).
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H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
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H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
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K. Wu, H. He, Y. Lu, J. Huang, and Z. Ye, “Dominant free exciton emission in ZnO nanorods,” Nanoscale 4(5), 1701–1706 (2012).
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X. Q. Gu, L. P. Zhu, Z. Z. Ye, H. P. He, Y. Z. Zhang, F. Huang, M. X. Qiu, Y. J. Zeng, F. Liu, and W. Jaeger, “Room-temperature photoluminescence from ZnO/ZnMgO multiple quantum wells grown on Si(111) substrates,” Appl. Phys. Lett. 91(2), 022103 (2007).
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M. Shimizu, Y. Kawaguchi, K. Hiramatsu, and N. Sawaki, “Metalorganic vapor phase epitaxy of thick InGaN on sapphire substrate,” Jpn. J. Appl. Phys. Part 1 36(Part 1, No. 6A), 3381–3384 (1997).
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Y. J. Chen, Y. Y. Shih, C. H. Ho, J. H. Du, and Y. P. Fu, “Effect of temperature on lateral growth of ZnO grains grown by MOCVD,” Ceram. Int. 36(1), 69–73 (2010).
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M. Brandt, H. Wenckstern, M. Stölzel, H. Hochmuth, M. Lorenz, and M. Grundmann, “Semiconducting oxide heterostructures,” Semicond. Sci. Technol. 26(1), 014040 (2011).
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Hong, S. K.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

Y. Chen, S. K. Hong, H. J. Ko, V. Kirshner, H. Wenisch, T. Yao, K. Inaba, and Y. Segawa, “Effects of an extremely thin buffer on heteroepitaxy with large lattice mismatch,” Appl. Phys. Lett. 78(21), 3352–3354 (2001).
[Crossref]

Y. Chen, H. J. Ko, S. K. Hong, and T. Yao, “Layer-by-layer growth of ZnO epilayer on Al2O3 (0001) by using a MgO buffer layer,” Appl. Phys. Lett. 76(5), 559–561 (2000).
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S. Y. Ting, P. J. Chen, H. C. Wang, C. H. Liao, W. M. Chang, Y. P. Hsieh, and C. C. Yang, “Crystallinity improvement of ZnO thin film on different buffer layers grown by MBE,” J. Nanomater. 2012, 6 (2012), doi:.
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Huang, F.

X. Q. Gu, L. P. Zhu, Z. Z. Ye, H. P. He, Y. Z. Zhang, F. Huang, M. X. Qiu, Y. J. Zeng, F. Liu, and W. Jaeger, “Room-temperature photoluminescence from ZnO/ZnMgO multiple quantum wells grown on Si(111) substrates,” Appl. Phys. Lett. 91(2), 022103 (2007).
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Huang, G. S.

G. Liu, J. Zhang, X. H. Li, G. S. Huang, T. Paskova, K. R. Evans, H. Zhao, and N. Tansu, “Metalorganic vapor phase epitaxy and characterizations of nearly-lattice-matched AlInN alloys on GaN/sapphire templates and free-standing GaN substrates,” J. Cryst. Growth 340(1), 66–73 (2012).
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H. P. Zhao, G. Y. Liu, X. H. Li, R. A. Arif, G. S. Huang, J. D. Poplawsky, S. Tafon Penn, V. Dierolf, and N. Tansu, “Design and characteristics of staggered InGaN quantum well light-emitting diodes in the green spectral regimes,” IET Optoelectron. 3(6), 283–295 (2009).
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Huang, H.

H. Long, G. Fang, S. Li, X. Mo, H. Wang, H. Huang, Q. Jiang, J. Wang, and X. Zhao, “A ZnO/ZnMgO multiple-quantum-well ultraviolet random laser diode,” IEEE Electron Device Lett. 32(1), 54–56 (2011).
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Huang, J.

K. Wu, H. He, Y. Lu, J. Huang, and Z. Ye, “Dominant free exciton emission in ZnO nanorods,” Nanoscale 4(5), 1701–1706 (2012).
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Hwang, D. K.

J. H. Lim, C. K. Kang, K. K. Kim, I. K. Park, D. K. Hwang, and S. J. Park, “UV electroluminescence emission from ZnO light-emitting diodes grown by high-temperature radiofrequency sputtering,” Adv. Mater.  18(20), 2720–2724 (2006).
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Ihm, Y. E.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
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Inaba, K.

Y. Chen, S. K. Hong, H. J. Ko, V. Kirshner, H. Wenisch, T. Yao, K. Inaba, and Y. Segawa, “Effects of an extremely thin buffer on heteroepitaxy with large lattice mismatch,” Appl. Phys. Lett. 78(21), 3352–3354 (2001).
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Inoue, M.

C. R. Hall, L. V. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, C. Jagadish, and J. A. Davis, “Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field,” Appl. Phys. Lett. 96(19), 193117 (2010).
[Crossref]

V. A. Coleman, M. Buda, H. H. Tan, C. Jagadish, M. R. Phillips, K. Koike, S. Sasa, M. Inoue, and M. Yano, “Observation of blue shifts in ZnO/ZnMgO multiple quantum well structures by ion-implantation induced intermixing,” Semicond. Sci. Technol. 21(3), L25–L28 (2006).
[Crossref]

K. Koike, G. Y. Takada, K. Fujimoto, S. Sasa, M. Inoue, and M. Yano, “Characterization of [ZnO]m[ZnMgO]n multiple quantum wells grown by molecular beam epitaxy,” Physica E 32(1-2), 191–194 (2006).
[Crossref]

K. Koike, I. Nakashima, K. Hashimoto, S. Sasa, M. Inoue, and M. Yano, “Characteristics of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor grown on sapphire substrate by molecular-beam epitaxy,” Appl. Phys. Lett. 87(11), 112106 (2005).
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A. El-Shaer, A. Bakin, M. Al-Suleiman, S. Ivanov, A. Che Mofor, and A. Waag, “Growth of wide band gap wurtzite ZnMgO layers on (0001) Al2O3 by radical-source molecular beam epitaxy,” Superlattices Microstruct. 42(1-6), 129–133 (2007).
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X. Q. Gu, L. P. Zhu, Z. Z. Ye, H. P. He, Y. Z. Zhang, F. Huang, M. X. Qiu, Y. J. Zeng, F. Liu, and W. Jaeger, “Room-temperature photoluminescence from ZnO/ZnMgO multiple quantum wells grown on Si(111) substrates,” Appl. Phys. Lett. 91(2), 022103 (2007).
[Crossref]

Jagadish, C.

C. R. Hall, L. V. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, C. Jagadish, and J. A. Davis, “Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field,” Appl. Phys. Lett. 96(19), 193117 (2010).
[Crossref]

V. A. Coleman, M. Buda, H. H. Tan, C. Jagadish, M. R. Phillips, K. Koike, S. Sasa, M. Inoue, and M. Yano, “Observation of blue shifts in ZnO/ZnMgO multiple quantum well structures by ion-implantation induced intermixing,” Semicond. Sci. Technol. 21(3), L25–L28 (2006).
[Crossref]

Jang, H. M.

W. I. Park, G. C. Yi, and H. M. Jang, “Metalorganic vapor-phase epitaxial growth and photoluminescent properties of Zn1−xMgxO(0 ≤ x ≤ 0.49) thin films,” Appl. Phys. Lett. 79(13), 2022–2024 (2001).
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Y. Chen, F. Jiang, L. Wang, C. Zheng, J. Dai, Y. Pu, and W. Fang, “Structural and luminescent properties of ZnO epitaxial film grown on Si(111) substrate by atmospheric-pressure MOCVD,” J. Cryst. Growth 275(3-4), 486–491 (2005).
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Jiang, Q.

H. Long, G. Fang, S. Li, X. Mo, H. Wang, H. Huang, Q. Jiang, J. Wang, and X. Zhao, “A ZnO/ZnMgO multiple-quantum-well ultraviolet random laser diode,” IEEE Electron Device Lett. 32(1), 54–56 (2011).
[Crossref]

Jouneau, P. H.

R. Thierry, G. Perillat-Merceroz, P. H. Jouneau, P. Ferret, and G. Feuillet, “Core-shell multi-quantum wells in ZnO/ZnMgO nanowires with high optical efficiency at room temperature,” Nanotechnology 23(8), 085705 (2012).
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J. H. Lim, C. K. Kang, K. K. Kim, I. K. Park, D. K. Hwang, and S. J. Park, “UV electroluminescence emission from ZnO light-emitting diodes grown by high-temperature radiofrequency sputtering,” Adv. Mater.  18(20), 2720–2724 (2006).
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Kasu, M.

Y. Taniyasu and M. Kasu, “Polarization property of deep-ultraviolet light emission from C-plane AlN/GaN short-period superlattices,” Appl. Phys. Lett. 99(25), 251112 (2011).
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H. Kato, K. Miyamoto, M. Sano, and T. Yao, “Polarity control of ZnO on sapphire by varying the MgO buffer layer thickness,” Appl. Phys. Lett. 84(22), 4562–4564 (2004).
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M. Shimizu, Y. Kawaguchi, K. Hiramatsu, and N. Sawaki, “Metalorganic vapor phase epitaxy of thick InGaN on sapphire substrate,” Jpn. J. Appl. Phys. Part 1 36(Part 1, No. 6A), 3381–3384 (1997).
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T. Makino, Y. Segawa, and M. Kawasaki, “Analytical study on exciton - longitudinal - optical - phonon coupling and comparison with experiment for ZnO quantum wells,” J. Appl. Phys. 97(10), 106111 (2005).
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T. Makino, Y. Segawa, M. Kawasaki, and H. Koinuma, “Optical properties of excitons in ZnO-based quantum well heterostructures,” Semicond. Sci. Technol. 20(4), S78–S91 (2005).
[Crossref]

T. Makino, K. Tamura, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, and H. Koinuma, “Effect of MgZnO-layer capping on optical properties of ZnO epitaxial layers,” Appl. Phys. Lett. 81(12), 2172–2174 (2002).
[Crossref]

D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Phonon replicas in ZnO/ZnMgO multiquantum wells,” J. Appl. Phys. 91(10), 6457–6460 (2002).
[Crossref]

T. Makino, Y. Segawa, M. Kawasaki, A. Ohtomo, R. Shiroki, K. Tamura, T. Yasuda, and H. Koinuma, “Band gap engineering based on MgxZn1−xO and CdyZn1−yO ternary alloy films,” Appl. Phys. Lett. 78(9), 1237–1239 (2001).
[Crossref]

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

T. Makino, C. H. Chia, N. T. Tuan, H. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Room-temperature luminescence of excitons in ZnO/(Mg,Zn) O multiple quantum wells on lattice-matched substrates,” Appl. Phys. Lett. 77(7), 975–977 (2000).
[Crossref]

A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
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R. B. Chung, F. Wu, R. Shivaraman, S. Keller, S. P. DenBaars, J. S. Speck, and S. Nakamura, “Growth study and ipurity characterization of AlxIn1−xN grown by metal organic chemical vapor deposition,” J. Cryst. Growth 324(1), 163–167 (2011).
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Kim, D.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

Kim, J. G.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

Kim, K. K.

J. H. Lim, C. K. Kang, K. K. Kim, I. K. Park, D. K. Hwang, and S. J. Park, “UV electroluminescence emission from ZnO light-emitting diodes grown by high-temperature radiofrequency sputtering,” Adv. Mater.  18(20), 2720–2724 (2006).
[Crossref]

Kioseoglou, J.

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
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A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

Kirchner, C.

T. Gruber, C. Kirchner, R. Kling, F. Reuss, and A. Waag, “ZnMgO epilayers and ZnO-ZnMgO quantum wells for optoelectronic applications in the blue and UV spectral region,” Appl. Phys. Lett. 84(26), 5359–5361 (2004).
[Crossref]

T. Gruber, C. Kirchner, R. Kling, F. Reuss, A. Waag, F. Bertram, D. Forster, J. Christen, and M. Schreck, “Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy,” Appl. Phys. Lett. 83(16), 3290–3292 (2003).
[Crossref]

Kirshner, V.

Y. Chen, S. K. Hong, H. J. Ko, V. Kirshner, H. Wenisch, T. Yao, K. Inaba, and Y. Segawa, “Effects of an extremely thin buffer on heteroepitaxy with large lattice mismatch,” Appl. Phys. Lett. 78(21), 3352–3354 (2001).
[Crossref]

Kling, R.

T. Gruber, C. Kirchner, R. Kling, F. Reuss, and A. Waag, “ZnMgO epilayers and ZnO-ZnMgO quantum wells for optoelectronic applications in the blue and UV spectral region,” Appl. Phys. Lett. 84(26), 5359–5361 (2004).
[Crossref]

T. Gruber, C. Kirchner, R. Kling, F. Reuss, A. Waag, F. Bertram, D. Forster, J. Christen, and M. Schreck, “Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy,” Appl. Phys. Lett. 83(16), 3290–3292 (2003).
[Crossref]

Ko, H. J.

Y. Chen, S. K. Hong, H. J. Ko, V. Kirshner, H. Wenisch, T. Yao, K. Inaba, and Y. Segawa, “Effects of an extremely thin buffer on heteroepitaxy with large lattice mismatch,” Appl. Phys. Lett. 78(21), 3352–3354 (2001).
[Crossref]

Y. Chen, H. J. Ko, S. K. Hong, and T. Yao, “Layer-by-layer growth of ZnO epilayer on Al2O3 (0001) by using a MgO buffer layer,” Appl. Phys. Lett. 76(5), 559–561 (2000).
[Crossref]

Koida, T.

A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
[Crossref]

Koike, K.

C. R. Hall, L. V. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, C. Jagadish, and J. A. Davis, “Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field,” Appl. Phys. Lett. 96(19), 193117 (2010).
[Crossref]

V. A. Coleman, M. Buda, H. H. Tan, C. Jagadish, M. R. Phillips, K. Koike, S. Sasa, M. Inoue, and M. Yano, “Observation of blue shifts in ZnO/ZnMgO multiple quantum well structures by ion-implantation induced intermixing,” Semicond. Sci. Technol. 21(3), L25–L28 (2006).
[Crossref]

K. Koike, G. Y. Takada, K. Fujimoto, S. Sasa, M. Inoue, and M. Yano, “Characterization of [ZnO]m[ZnMgO]n multiple quantum wells grown by molecular beam epitaxy,” Physica E 32(1-2), 191–194 (2006).
[Crossref]

K. Koike, I. Nakashima, K. Hashimoto, S. Sasa, M. Inoue, and M. Yano, “Characteristics of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor grown on sapphire substrate by molecular-beam epitaxy,” Appl. Phys. Lett. 87(11), 112106 (2005).
[Crossref]

Koinuma, H.

T. Makino, Y. Segawa, M. Kawasaki, and H. Koinuma, “Optical properties of excitons in ZnO-based quantum well heterostructures,” Semicond. Sci. Technol. 20(4), S78–S91 (2005).
[Crossref]

D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Phonon replicas in ZnO/ZnMgO multiquantum wells,” J. Appl. Phys. 91(10), 6457–6460 (2002).
[Crossref]

T. Makino, K. Tamura, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, and H. Koinuma, “Effect of MgZnO-layer capping on optical properties of ZnO epitaxial layers,” Appl. Phys. Lett. 81(12), 2172–2174 (2002).
[Crossref]

T. Makino, Y. Segawa, M. Kawasaki, A. Ohtomo, R. Shiroki, K. Tamura, T. Yasuda, and H. Koinuma, “Band gap engineering based on MgxZn1−xO and CdyZn1−yO ternary alloy films,” Appl. Phys. Lett. 78(9), 1237–1239 (2001).
[Crossref]

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

T. Makino, C. H. Chia, N. T. Tuan, H. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Room-temperature luminescence of excitons in ZnO/(Mg,Zn) O multiple quantum wells on lattice-matched substrates,” Appl. Phys. Lett. 77(7), 975–977 (2000).
[Crossref]

A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
[Crossref]

Koyama, S.

D. M. Bagnall, Y. F. Chen, Z. Zhu, T. Yao, S. Koyama, M. Y. Shen, and T. Goto, “Optically pumped lasing of ZnO at room temperature,” Appl. Phys. Lett. 70(17), 2230–2232 (1997).
[Crossref]

Lange, M.

M. Brandt, M. Lange, M. Stölzel, A. Müller, G. Benndorf, J. Zippel, J. Lenzner, M. Lorenz, and M. Grundmann, “Control of interface abruptness of polar MgZnO/ZnO quantum wells grown by pulsed laser deposition,” Appl. Phys. Lett. 97(5), 052101 (2010).
[Crossref]

Lee, C.-G.

S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008).
[Crossref]

Lee, H. J.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

Lee, J. W.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

Lee, J. Y.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

Lenzner, J.

M. Brandt, M. Lange, M. Stölzel, A. Müller, G. Benndorf, J. Zippel, J. Lenzner, M. Lorenz, and M. Grundmann, “Control of interface abruptness of polar MgZnO/ZnO quantum wells grown by pulsed laser deposition,” Appl. Phys. Lett. 97(5), 052101 (2010).
[Crossref]

Li, S.

H. Long, G. Fang, S. Li, X. Mo, H. Wang, H. Huang, Q. Jiang, J. Wang, and X. Zhao, “A ZnO/ZnMgO multiple-quantum-well ultraviolet random laser diode,” IEEE Electron Device Lett. 32(1), 54–56 (2011).
[Crossref]

Li, X. H.

G. Liu, J. Zhang, X. H. Li, G. S. Huang, T. Paskova, K. R. Evans, H. Zhao, and N. Tansu, “Metalorganic vapor phase epitaxy and characterizations of nearly-lattice-matched AlInN alloys on GaN/sapphire templates and free-standing GaN substrates,” J. Cryst. Growth 340(1), 66–73 (2012).
[Crossref]

H. P. Zhao, G. Y. Liu, X. H. Li, R. A. Arif, G. S. Huang, J. D. Poplawsky, S. Tafon Penn, V. Dierolf, and N. Tansu, “Design and characteristics of staggered InGaN quantum well light-emitting diodes in the green spectral regimes,” IET Optoelectron. 3(6), 283–295 (2009).
[Crossref]

Liao, C. H.

S. Y. Ting, P. J. Chen, H. C. Wang, C. H. Liao, W. M. Chang, Y. P. Hsieh, and C. C. Yang, “Crystallinity improvement of ZnO thin film on different buffer layers grown by MBE,” J. Nanomater. 2012, 6 (2012), doi:.
[Crossref]

Lim, J. H.

J. H. Lim, C. K. Kang, K. K. Kim, I. K. Park, D. K. Hwang, and S. J. Park, “UV electroluminescence emission from ZnO light-emitting diodes grown by high-temperature radiofrequency sputtering,” Adv. Mater.  18(20), 2720–2724 (2006).
[Crossref]

Liu, F.

X. Q. Gu, L. P. Zhu, Z. Z. Ye, H. P. He, Y. Z. Zhang, F. Huang, M. X. Qiu, Y. J. Zeng, F. Liu, and W. Jaeger, “Room-temperature photoluminescence from ZnO/ZnMgO multiple quantum wells grown on Si(111) substrates,” Appl. Phys. Lett. 91(2), 022103 (2007).
[Crossref]

Liu, G.

G. Liu, J. Zhang, X. H. Li, G. S. Huang, T. Paskova, K. R. Evans, H. Zhao, and N. Tansu, “Metalorganic vapor phase epitaxy and characterizations of nearly-lattice-matched AlInN alloys on GaN/sapphire templates and free-standing GaN substrates,” J. Cryst. Growth 340(1), 66–73 (2012).
[Crossref]

Liu, G. Y.

H. P. Zhao, G. Y. Liu, J. Zhang, J. D. Poplawsky, V. Dierolf, and N. Tansu, “Approaches for high internal quantum efficiency green InGaN light-emitting diodes with large overlap quantum wells,” Opt. Express 19(S4Suppl 4), A991–A1007 (2011).
[Crossref] [PubMed]

H. P. Zhao, G. Y. Liu, X. H. Li, R. A. Arif, G. S. Huang, J. D. Poplawsky, S. Tafon Penn, V. Dierolf, and N. Tansu, “Design and characteristics of staggered InGaN quantum well light-emitting diodes in the green spectral regimes,” IET Optoelectron. 3(6), 283–295 (2009).
[Crossref]

Long, H.

H. Long, G. Fang, S. Li, X. Mo, H. Wang, H. Huang, Q. Jiang, J. Wang, and X. Zhao, “A ZnO/ZnMgO multiple-quantum-well ultraviolet random laser diode,” IEEE Electron Device Lett. 32(1), 54–56 (2011).
[Crossref]

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D. C. Look, “Recent advances in ZnO materials and devices,” Mater. Sci. Eng. B 80(1-3), 383–387 (2001).
[Crossref]

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M. Brandt, H. Wenckstern, M. Stölzel, H. Hochmuth, M. Lorenz, and M. Grundmann, “Semiconducting oxide heterostructures,” Semicond. Sci. Technol. 26(1), 014040 (2011).
[Crossref]

M. Brandt, M. Lange, M. Stölzel, A. Müller, G. Benndorf, J. Zippel, J. Lenzner, M. Lorenz, and M. Grundmann, “Control of interface abruptness of polar MgZnO/ZnO quantum wells grown by pulsed laser deposition,” Appl. Phys. Lett. 97(5), 052101 (2010).
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Lu, Y.

K. Wu, H. He, Y. Lu, J. Huang, and Z. Ye, “Dominant free exciton emission in ZnO nanorods,” Nanoscale 4(5), 1701–1706 (2012).
[Crossref] [PubMed]

Makino, T.

T. Makino, Y. Segawa, and M. Kawasaki, “Analytical study on exciton - longitudinal - optical - phonon coupling and comparison with experiment for ZnO quantum wells,” J. Appl. Phys. 97(10), 106111 (2005).
[Crossref]

T. Makino, Y. Segawa, M. Kawasaki, and H. Koinuma, “Optical properties of excitons in ZnO-based quantum well heterostructures,” Semicond. Sci. Technol. 20(4), S78–S91 (2005).
[Crossref]

T. Makino, K. Tamura, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, and H. Koinuma, “Effect of MgZnO-layer capping on optical properties of ZnO epitaxial layers,” Appl. Phys. Lett. 81(12), 2172–2174 (2002).
[Crossref]

T. Makino, Y. Segawa, M. Kawasaki, A. Ohtomo, R. Shiroki, K. Tamura, T. Yasuda, and H. Koinuma, “Band gap engineering based on MgxZn1−xO and CdyZn1−yO ternary alloy films,” Appl. Phys. Lett. 78(9), 1237–1239 (2001).
[Crossref]

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

T. Makino, C. H. Chia, N. T. Tuan, H. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Room-temperature luminescence of excitons in ZnO/(Mg,Zn) O multiple quantum wells on lattice-matched substrates,” Appl. Phys. Lett. 77(7), 975–977 (2000).
[Crossref]

Mallett, J.

S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008).
[Crossref]

Masubuchi, K.

A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
[Crossref]

Matsui, H.

H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
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H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
[Crossref]

Miyamoto, K.

H. Kato, K. Miyamoto, M. Sano, and T. Yao, “Polarity control of ZnO on sapphire by varying the MgO buffer layer thickness,” Appl. Phys. Lett. 84(22), 4562–4564 (2004).
[Crossref]

Mo, X.

H. Long, G. Fang, S. Li, X. Mo, H. Wang, H. Huang, Q. Jiang, J. Wang, and X. Zhao, “A ZnO/ZnMgO multiple-quantum-well ultraviolet random laser diode,” IEEE Electron Device Lett. 32(1), 54–56 (2011).
[Crossref]

Mofor, A.-C.

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

Moustakas, T. D.

E. Francesco Pecora, W. Zhang, A. Yu. Nikiforov, L. Zhou, D. J. Smith, J. Yin, R. Paiella, L. Dal Negro, and T. D. Moustakas, “Sub-250 nm room-temperature optical gain from AlGaN/AlN multiple quantum wells with strong band-structure potential fluctuations,” Appl. Phys. Lett. 100(6), 061111 (2012).
[Crossref]

Müller, A.

M. Brandt, M. Lange, M. Stölzel, A. Müller, G. Benndorf, J. Zippel, J. Lenzner, M. Lorenz, and M. Grundmann, “Control of interface abruptness of polar MgZnO/ZnO quantum wells grown by pulsed laser deposition,” Appl. Phys. Lett. 97(5), 052101 (2010).
[Crossref]

Nakagawa, D.

T. Sugahara, M. Hao, T. Wang, D. Nakagawa, Y. Naoi, K. Nishino, and S. Sakai, “Role of dislocation in InGaN phase separation,” Jpn. J. Appl. Phys. Part 2 37(Part 2, No. 10B), L1195–L1198 (1998).
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Nakamura, S.

R. B. Chung, F. Wu, R. Shivaraman, S. Keller, S. P. DenBaars, J. S. Speck, and S. Nakamura, “Growth study and ipurity characterization of AlxIn1−xN grown by metal organic chemical vapor deposition,” J. Cryst. Growth 324(1), 163–167 (2011).
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Nakashima, I.

K. Koike, I. Nakashima, K. Hashimoto, S. Sasa, M. Inoue, and M. Yano, “Characteristics of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor grown on sapphire substrate by molecular-beam epitaxy,” Appl. Phys. Lett. 87(11), 112106 (2005).
[Crossref]

Naoi, Y.

T. Sugahara, M. Hao, T. Wang, D. Nakagawa, Y. Naoi, K. Nishino, and S. Sakai, “Role of dislocation in InGaN phase separation,” Jpn. J. Appl. Phys. Part 2 37(Part 2, No. 10B), L1195–L1198 (1998).
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Nishino, K.

T. Sugahara, M. Hao, T. Wang, D. Nakagawa, Y. Naoi, K. Nishino, and S. Sakai, “Role of dislocation in InGaN phase separation,” Jpn. J. Appl. Phys. Part 2 37(Part 2, No. 10B), L1195–L1198 (1998).
[Crossref]

O, S. Y.

S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008).
[Crossref]

O’Donnell, K. P.

S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
[Crossref]

Ohtomo, A.

T. Makino, K. Tamura, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, and H. Koinuma, “Effect of MgZnO-layer capping on optical properties of ZnO epitaxial layers,” Appl. Phys. Lett. 81(12), 2172–2174 (2002).
[Crossref]

D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Phonon replicas in ZnO/ZnMgO multiquantum wells,” J. Appl. Phys. 91(10), 6457–6460 (2002).
[Crossref]

T. Makino, Y. Segawa, M. Kawasaki, A. Ohtomo, R. Shiroki, K. Tamura, T. Yasuda, and H. Koinuma, “Band gap engineering based on MgxZn1−xO and CdyZn1−yO ternary alloy films,” Appl. Phys. Lett. 78(9), 1237–1239 (2001).
[Crossref]

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

T. Makino, C. H. Chia, N. T. Tuan, H. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Room-temperature luminescence of excitons in ZnO/(Mg,Zn) O multiple quantum wells on lattice-matched substrates,” Appl. Phys. Lett. 77(7), 975–977 (2000).
[Crossref]

A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
[Crossref]

Paiella, R.

E. Francesco Pecora, W. Zhang, A. Yu. Nikiforov, L. Zhou, D. J. Smith, J. Yin, R. Paiella, L. Dal Negro, and T. D. Moustakas, “Sub-250 nm room-temperature optical gain from AlGaN/AlN multiple quantum wells with strong band-structure potential fluctuations,” Appl. Phys. Lett. 100(6), 061111 (2012).
[Crossref]

Park, I. K.

J. H. Lim, C. K. Kang, K. K. Kim, I. K. Park, D. K. Hwang, and S. J. Park, “UV electroluminescence emission from ZnO light-emitting diodes grown by high-temperature radiofrequency sputtering,” Adv. Mater.  18(20), 2720–2724 (2006).
[Crossref]

Park, J. S.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

Park, S. J.

J. H. Lim, C. K. Kang, K. K. Kim, I. K. Park, D. K. Hwang, and S. J. Park, “UV electroluminescence emission from ZnO light-emitting diodes grown by high-temperature radiofrequency sputtering,” Adv. Mater.  18(20), 2720–2724 (2006).
[Crossref]

Park, W. I.

W. I. Park, G. C. Yi, and H. M. Jang, “Metalorganic vapor-phase epitaxial growth and photoluminescent properties of Zn1−xMgxO(0 ≤ x ≤ 0.49) thin films,” Appl. Phys. Lett. 79(13), 2022–2024 (2001).
[Crossref]

Paskova, T.

G. Liu, J. Zhang, X. H. Li, G. S. Huang, T. Paskova, K. R. Evans, H. Zhao, and N. Tansu, “Metalorganic vapor phase epitaxy and characterizations of nearly-lattice-matched AlInN alloys on GaN/sapphire templates and free-standing GaN substrates,” J. Cryst. Growth 340(1), 66–73 (2012).
[Crossref]

Pecz, B.

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

Pereira, E.

S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
[Crossref]

Pereira, S.

S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
[Crossref]

Perillat-Merceroz, G.

R. Thierry, G. Perillat-Merceroz, P. H. Jouneau, P. Ferret, and G. Feuillet, “Core-shell multi-quantum wells in ZnO/ZnMgO nanowires with high optical efficiency at room temperature,” Nanotechnology 23(8), 085705 (2012).
[Crossref] [PubMed]

Phillips, M. R.

V. A. Coleman, M. Buda, H. H. Tan, C. Jagadish, M. R. Phillips, K. Koike, S. Sasa, M. Inoue, and M. Yano, “Observation of blue shifts in ZnO/ZnMgO multiple quantum well structures by ion-implantation induced intermixing,” Semicond. Sci. Technol. 21(3), L25–L28 (2006).
[Crossref]

Pong, P. W. T.

S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008).
[Crossref]

Poplawsky, J. D.

H. P. Zhao, G. Y. Liu, J. Zhang, J. D. Poplawsky, V. Dierolf, and N. Tansu, “Approaches for high internal quantum efficiency green InGaN light-emitting diodes with large overlap quantum wells,” Opt. Express 19(S4Suppl 4), A991–A1007 (2011).
[Crossref] [PubMed]

H. P. Zhao, G. Y. Liu, X. H. Li, R. A. Arif, G. S. Huang, J. D. Poplawsky, S. Tafon Penn, V. Dierolf, and N. Tansu, “Design and characteristics of staggered InGaN quantum well light-emitting diodes in the green spectral regimes,” IET Optoelectron. 3(6), 283–295 (2009).
[Crossref]

Pu, Y.

Y. Chen, F. Jiang, L. Wang, C. Zheng, J. Dai, Y. Pu, and W. Fang, “Structural and luminescent properties of ZnO epitaxial film grown on Si(111) substrate by atmospheric-pressure MOCVD,” J. Cryst. Growth 275(3-4), 486–491 (2005).
[Crossref]

Qiu, M. X.

X. Q. Gu, L. P. Zhu, Z. Z. Ye, H. P. He, Y. Z. Zhang, F. Huang, M. X. Qiu, Y. J. Zeng, F. Liu, and W. Jaeger, “Room-temperature photoluminescence from ZnO/ZnMgO multiple quantum wells grown on Si(111) substrates,” Appl. Phys. Lett. 91(2), 022103 (2007).
[Crossref]

Reuss, F.

T. Gruber, C. Kirchner, R. Kling, F. Reuss, and A. Waag, “ZnMgO epilayers and ZnO-ZnMgO quantum wells for optoelectronic applications in the blue and UV spectral region,” Appl. Phys. Lett. 84(26), 5359–5361 (2004).
[Crossref]

T. Gruber, C. Kirchner, R. Kling, F. Reuss, A. Waag, F. Bertram, D. Forster, J. Christen, and M. Schreck, “Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy,” Appl. Phys. Lett. 83(16), 3290–3292 (2003).
[Crossref]

Ruglovsky, J. L.

S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008).
[Crossref]

Saito, S.

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

Sakai, S.

T. Sugahara, M. Hao, T. Wang, D. Nakagawa, Y. Naoi, K. Nishino, and S. Sakai, “Role of dislocation in InGaN phase separation,” Jpn. J. Appl. Phys. Part 2 37(Part 2, No. 10B), L1195–L1198 (1998).
[Crossref]

Sakurai, Y.

A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
[Crossref]

Sano, M.

H. Kato, K. Miyamoto, M. Sano, and T. Yao, “Polarity control of ZnO on sapphire by varying the MgO buffer layer thickness,” Appl. Phys. Lett. 84(22), 4562–4564 (2004).
[Crossref]

Sasa, S.

C. R. Hall, L. V. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, C. Jagadish, and J. A. Davis, “Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field,” Appl. Phys. Lett. 96(19), 193117 (2010).
[Crossref]

V. A. Coleman, M. Buda, H. H. Tan, C. Jagadish, M. R. Phillips, K. Koike, S. Sasa, M. Inoue, and M. Yano, “Observation of blue shifts in ZnO/ZnMgO multiple quantum well structures by ion-implantation induced intermixing,” Semicond. Sci. Technol. 21(3), L25–L28 (2006).
[Crossref]

K. Koike, G. Y. Takada, K. Fujimoto, S. Sasa, M. Inoue, and M. Yano, “Characterization of [ZnO]m[ZnMgO]n multiple quantum wells grown by molecular beam epitaxy,” Physica E 32(1-2), 191–194 (2006).
[Crossref]

K. Koike, I. Nakashima, K. Hashimoto, S. Sasa, M. Inoue, and M. Yano, “Characteristics of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor grown on sapphire substrate by molecular-beam epitaxy,” Appl. Phys. Lett. 87(11), 112106 (2005).
[Crossref]

Sawaki, N.

M. Shimizu, Y. Kawaguchi, K. Hiramatsu, and N. Sawaki, “Metalorganic vapor phase epitaxy of thick InGaN on sapphire substrate,” Jpn. J. Appl. Phys. Part 1 36(Part 1, No. 6A), 3381–3384 (1997).
[Crossref]

Schreck, M.

T. Gruber, C. Kirchner, R. Kling, F. Reuss, A. Waag, F. Bertram, D. Forster, J. Christen, and M. Schreck, “Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy,” Appl. Phys. Lett. 83(16), 3290–3292 (2003).
[Crossref]

Segawa, Y.

T. Makino, Y. Segawa, M. Kawasaki, and H. Koinuma, “Optical properties of excitons in ZnO-based quantum well heterostructures,” Semicond. Sci. Technol. 20(4), S78–S91 (2005).
[Crossref]

T. Makino, Y. Segawa, and M. Kawasaki, “Analytical study on exciton - longitudinal - optical - phonon coupling and comparison with experiment for ZnO quantum wells,” J. Appl. Phys. 97(10), 106111 (2005).
[Crossref]

T. Makino, K. Tamura, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, and H. Koinuma, “Effect of MgZnO-layer capping on optical properties of ZnO epitaxial layers,” Appl. Phys. Lett. 81(12), 2172–2174 (2002).
[Crossref]

D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Phonon replicas in ZnO/ZnMgO multiquantum wells,” J. Appl. Phys. 91(10), 6457–6460 (2002).
[Crossref]

Y. Chen, S. K. Hong, H. J. Ko, V. Kirshner, H. Wenisch, T. Yao, K. Inaba, and Y. Segawa, “Effects of an extremely thin buffer on heteroepitaxy with large lattice mismatch,” Appl. Phys. Lett. 78(21), 3352–3354 (2001).
[Crossref]

T. Makino, Y. Segawa, M. Kawasaki, A. Ohtomo, R. Shiroki, K. Tamura, T. Yasuda, and H. Koinuma, “Band gap engineering based on MgxZn1−xO and CdyZn1−yO ternary alloy films,” Appl. Phys. Lett. 78(9), 1237–1239 (2001).
[Crossref]

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

T. Makino, C. H. Chia, N. T. Tuan, H. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Room-temperature luminescence of excitons in ZnO/(Mg,Zn) O multiple quantum wells on lattice-matched substrates,” Appl. Phys. Lett. 77(7), 975–977 (2000).
[Crossref]

A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
[Crossref]

Sequeira, A. D.

S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
[Crossref]

Shapiro, A. J.

S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008).
[Crossref]

Shen, M. Y.

D. M. Bagnall, Y. F. Chen, Z. Zhu, T. Yao, S. Koyama, M. Y. Shen, and T. Goto, “Optically pumped lasing of ZnO at room temperature,” Appl. Phys. Lett. 70(17), 2230–2232 (1997).
[Crossref]

Shih, Y. Y.

Y. J. Chen, Y. Y. Shih, C. H. Ho, J. H. Du, and Y. P. Fu, “Effect of temperature on lateral growth of ZnO grains grown by MOCVD,” Ceram. Int. 36(1), 69–73 (2010).
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Shimizu, M.

M. Shimizu, Y. Kawaguchi, K. Hiramatsu, and N. Sawaki, “Metalorganic vapor phase epitaxy of thick InGaN on sapphire substrate,” Jpn. J. Appl. Phys. Part 1 36(Part 1, No. 6A), 3381–3384 (1997).
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Shiroki, R.

T. Makino, Y. Segawa, M. Kawasaki, A. Ohtomo, R. Shiroki, K. Tamura, T. Yasuda, and H. Koinuma, “Band gap engineering based on MgxZn1−xO and CdyZn1−yO ternary alloy films,” Appl. Phys. Lett. 78(9), 1237–1239 (2001).
[Crossref]

Shivaraman, R.

R. B. Chung, F. Wu, R. Shivaraman, S. Keller, S. P. DenBaars, J. S. Speck, and S. Nakamura, “Growth study and ipurity characterization of AlxIn1−xN grown by metal organic chemical vapor deposition,” J. Cryst. Growth 324(1), 163–167 (2011).
[Crossref]

Smith, D. J.

E. Francesco Pecora, W. Zhang, A. Yu. Nikiforov, L. Zhou, D. J. Smith, J. Yin, R. Paiella, L. Dal Negro, and T. D. Moustakas, “Sub-250 nm room-temperature optical gain from AlGaN/AlN multiple quantum wells with strong band-structure potential fluctuations,” Appl. Phys. Lett. 100(6), 061111 (2012).
[Crossref]

Song, J. H.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

Speck, J. S.

R. B. Chung, F. Wu, R. Shivaraman, S. Keller, S. P. DenBaars, J. S. Speck, and S. Nakamura, “Growth study and ipurity characterization of AlxIn1−xN grown by metal organic chemical vapor deposition,” J. Cryst. Growth 324(1), 163–167 (2011).
[Crossref]

Stoemenos, J.

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

Stölzel, M.

M. Brandt, H. Wenckstern, M. Stölzel, H. Hochmuth, M. Lorenz, and M. Grundmann, “Semiconducting oxide heterostructures,” Semicond. Sci. Technol. 26(1), 014040 (2011).
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M. Brandt, M. Lange, M. Stölzel, A. Müller, G. Benndorf, J. Zippel, J. Lenzner, M. Lorenz, and M. Grundmann, “Control of interface abruptness of polar MgZnO/ZnO quantum wells grown by pulsed laser deposition,” Appl. Phys. Lett. 97(5), 052101 (2010).
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T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

Sugahara, T.

T. Sugahara, M. Hao, T. Wang, D. Nakagawa, Y. Naoi, K. Nishino, and S. Sakai, “Role of dislocation in InGaN phase separation,” Jpn. J. Appl. Phys. Part 2 37(Part 2, No. 10B), L1195–L1198 (1998).
[Crossref]

Sun, D.

D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Phonon replicas in ZnO/ZnMgO multiquantum wells,” J. Appl. Phys. 91(10), 6457–6460 (2002).
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Sun, H. D.

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

T. Makino, C. H. Chia, N. T. Tuan, H. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Room-temperature luminescence of excitons in ZnO/(Mg,Zn) O multiple quantum wells on lattice-matched substrates,” Appl. Phys. Lett. 77(7), 975–977 (2000).
[Crossref]

Sweeney, F.

S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
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Tabata, H.

H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
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H. Matsui, H. Tabata, N. Hasuike, and H. Harima, “Critical thickness and lattice relaxation of Mg-rich strained Mg0.37Zn0.63O (0001) layers towards multi-quantum-wells,” J. Appl. Phys. 99(2), 024902 (2006).
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Tafon Penn, S.

H. P. Zhao, G. Y. Liu, X. H. Li, R. A. Arif, G. S. Huang, J. D. Poplawsky, S. Tafon Penn, V. Dierolf, and N. Tansu, “Design and characteristics of staggered InGaN quantum well light-emitting diodes in the green spectral regimes,” IET Optoelectron. 3(6), 283–295 (2009).
[Crossref]

Takada, G. Y.

K. Koike, G. Y. Takada, K. Fujimoto, S. Sasa, M. Inoue, and M. Yano, “Characterization of [ZnO]m[ZnMgO]n multiple quantum wells grown by molecular beam epitaxy,” Physica E 32(1-2), 191–194 (2006).
[Crossref]

Tamura, K.

D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Phonon replicas in ZnO/ZnMgO multiquantum wells,” J. Appl. Phys. 91(10), 6457–6460 (2002).
[Crossref]

T. Makino, K. Tamura, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, and H. Koinuma, “Effect of MgZnO-layer capping on optical properties of ZnO epitaxial layers,” Appl. Phys. Lett. 81(12), 2172–2174 (2002).
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T. Makino, Y. Segawa, M. Kawasaki, A. Ohtomo, R. Shiroki, K. Tamura, T. Yasuda, and H. Koinuma, “Band gap engineering based on MgxZn1−xO and CdyZn1−yO ternary alloy films,” Appl. Phys. Lett. 78(9), 1237–1239 (2001).
[Crossref]

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

T. Makino, C. H. Chia, N. T. Tuan, H. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Room-temperature luminescence of excitons in ZnO/(Mg,Zn) O multiple quantum wells on lattice-matched substrates,” Appl. Phys. Lett. 77(7), 975–977 (2000).
[Crossref]

Tan, H. H.

C. R. Hall, L. V. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, C. Jagadish, and J. A. Davis, “Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field,” Appl. Phys. Lett. 96(19), 193117 (2010).
[Crossref]

V. A. Coleman, M. Buda, H. H. Tan, C. Jagadish, M. R. Phillips, K. Koike, S. Sasa, M. Inoue, and M. Yano, “Observation of blue shifts in ZnO/ZnMgO multiple quantum well structures by ion-implantation induced intermixing,” Semicond. Sci. Technol. 21(3), L25–L28 (2006).
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Y. Taniyasu and M. Kasu, “Polarization property of deep-ultraviolet light emission from C-plane AlN/GaN short-period superlattices,” Appl. Phys. Lett. 99(25), 251112 (2011).
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G. Liu, J. Zhang, X. H. Li, G. S. Huang, T. Paskova, K. R. Evans, H. Zhao, and N. Tansu, “Metalorganic vapor phase epitaxy and characterizations of nearly-lattice-matched AlInN alloys on GaN/sapphire templates and free-standing GaN substrates,” J. Cryst. Growth 340(1), 66–73 (2012).
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J. Zhang, H. Zhao, and N. Tansu, “Large optical gain AlGaN-delta-GaN quantum wells laser active regions in mid- and deep-ultraviolet spectral regimes,” Appl. Phys. Lett. 98(17), 171111 (2011).
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H. P. Zhao, G. Y. Liu, J. Zhang, J. D. Poplawsky, V. Dierolf, and N. Tansu, “Approaches for high internal quantum efficiency green InGaN light-emitting diodes with large overlap quantum wells,” Opt. Express 19(S4Suppl 4), A991–A1007 (2011).
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J. Zhang, H. Zhao, and N. Tansu, “Effect of crystal-field split-off hole and heavy-hole bands crossover on gain characteristics of high Al-content AlGaN quantum well lasers,” Appl. Phys. Lett. 97(11), 111105 (2010).
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H. P. Zhao, G. Y. Liu, X. H. Li, R. A. Arif, G. S. Huang, J. D. Poplawsky, S. Tafon Penn, V. Dierolf, and N. Tansu, “Design and characteristics of staggered InGaN quantum well light-emitting diodes in the green spectral regimes,” IET Optoelectron. 3(6), 283–295 (2009).
[Crossref]

R. A. Arif, Y.-K. Ee, and N. Tansu, “Polarization engineering via staggered InGaN quantum wells for radiative efficiency enhancement of light emitting diodes,” Appl. Phys. Lett. 91(9), 091110 (2007).
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Thierry, R.

R. Thierry, G. Perillat-Merceroz, P. H. Jouneau, P. Ferret, and G. Feuillet, “Core-shell multi-quantum wells in ZnO/ZnMgO nanowires with high optical efficiency at room temperature,” Nanotechnology 23(8), 085705 (2012).
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Ting, S. Y.

S. Y. Ting, P. J. Chen, H. C. Wang, C. H. Liao, W. M. Chang, Y. P. Hsieh, and C. C. Yang, “Crystallinity improvement of ZnO thin film on different buffer layers grown by MBE,” J. Nanomater. 2012, 6 (2012), doi:.
[Crossref]

Tomita, T.

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

Trager-Cowan, C.

S. Pereira, M. R. Correia, E. Pereira, C. Trager-Cowan, F. Sweeney, K. P. O’Donnell, E. Alves, N. Franco, and A. D. Sequeira, “Structural and optical properties of InGaN/GaN layers close to the critical layer thickness,” Appl. Phys. Lett. 81(7), 1207–1209 (2002).
[Crossref]

Tuan, N. T.

T. Makino, N. T. Tuan, H. D. Sun, C. H. Chia, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, T. Suemoto, H. Akiyama, M. Baba, S. Saito, T. Tomita, and H. Koinuma, “Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg,Zn)O multiple quantum wells,” Appl. Phys. Lett. 78(14), 1979–1981 (2001).
[Crossref]

T. Makino, C. H. Chia, N. T. Tuan, H. D. Sun, Y. Segawa, M. Kawasaki, A. Ohtomo, K. Tamura, and H. Koinuma, “Room-temperature luminescence of excitons in ZnO/(Mg,Zn) O multiple quantum wells on lattice-matched substrates,” Appl. Phys. Lett. 77(7), 975–977 (2000).
[Crossref]

Vaudin, M. D.

S. Y. O, C.-G. Lee, A. J. Shapiro, W. F. Egelhoff, M. D. Vaudin, J. L. Ruglovsky, J. Mallett, and P. W. T. Pong, “X-ray diffraction study of the optimization of MgO growth conditions for magnetic tunnel junctions,” J. Appl. Phys. 103(7), 07A920 (2008).
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Waag, A.

A. El-Shaer, A. Bakin, M. Al-Suleiman, S. Ivanov, A. Che Mofor, and A. Waag, “Growth of wide band gap wurtzite ZnMgO layers on (0001) Al2O3 by radical-source molecular beam epitaxy,” Superlattices Microstruct. 42(1-6), 129–133 (2007).
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A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
[Crossref]

A. Bakin, J. Kioseoglou, B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, and A. Waag, “Misfit reduction by a spinel layer formed during the epitaxial growth of ZnO on sapphire using a MgO buffer layer,” J. Cryst. Growth 308(2), 314–320 (2007).
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T. Gruber, C. Kirchner, R. Kling, F. Reuss, and A. Waag, “ZnMgO epilayers and ZnO-ZnMgO quantum wells for optoelectronic applications in the blue and UV spectral region,” Appl. Phys. Lett. 84(26), 5359–5361 (2004).
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T. Gruber, C. Kirchner, R. Kling, F. Reuss, A. Waag, F. Bertram, D. Forster, J. Christen, and M. Schreck, “Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy,” Appl. Phys. Lett. 83(16), 3290–3292 (2003).
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Wang, H.

H. Long, G. Fang, S. Li, X. Mo, H. Wang, H. Huang, Q. Jiang, J. Wang, and X. Zhao, “A ZnO/ZnMgO multiple-quantum-well ultraviolet random laser diode,” IEEE Electron Device Lett. 32(1), 54–56 (2011).
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Wang, H. C.

S. Y. Ting, P. J. Chen, H. C. Wang, C. H. Liao, W. M. Chang, Y. P. Hsieh, and C. C. Yang, “Crystallinity improvement of ZnO thin film on different buffer layers grown by MBE,” J. Nanomater. 2012, 6 (2012), doi:.
[Crossref]

Wang, J.

H. Long, G. Fang, S. Li, X. Mo, H. Wang, H. Huang, Q. Jiang, J. Wang, and X. Zhao, “A ZnO/ZnMgO multiple-quantum-well ultraviolet random laser diode,” IEEE Electron Device Lett. 32(1), 54–56 (2011).
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Wang, L.

Y. Chen, F. Jiang, L. Wang, C. Zheng, J. Dai, Y. Pu, and W. Fang, “Structural and luminescent properties of ZnO epitaxial film grown on Si(111) substrate by atmospheric-pressure MOCVD,” J. Cryst. Growth 275(3-4), 486–491 (2005).
[Crossref]

Wang, T.

T. Sugahara, M. Hao, T. Wang, D. Nakagawa, Y. Naoi, K. Nishino, and S. Sakai, “Role of dislocation in InGaN phase separation,” Jpn. J. Appl. Phys. Part 2 37(Part 2, No. 10B), L1195–L1198 (1998).
[Crossref]

Wenckstern, H.

M. Brandt, H. Wenckstern, M. Stölzel, H. Hochmuth, M. Lorenz, and M. Grundmann, “Semiconducting oxide heterostructures,” Semicond. Sci. Technol. 26(1), 014040 (2011).
[Crossref]

Wenisch, H.

Y. Chen, S. K. Hong, H. J. Ko, V. Kirshner, H. Wenisch, T. Yao, K. Inaba, and Y. Segawa, “Effects of an extremely thin buffer on heteroepitaxy with large lattice mismatch,” Appl. Phys. Lett. 78(21), 3352–3354 (2001).
[Crossref]

Wu, F.

R. B. Chung, F. Wu, R. Shivaraman, S. Keller, S. P. DenBaars, J. S. Speck, and S. Nakamura, “Growth study and ipurity characterization of AlxIn1−xN grown by metal organic chemical vapor deposition,” J. Cryst. Growth 324(1), 163–167 (2011).
[Crossref]

Wu, K.

K. Wu, H. He, Y. Lu, J. Huang, and Z. Ye, “Dominant free exciton emission in ZnO nanorods,” Nanoscale 4(5), 1701–1706 (2012).
[Crossref] [PubMed]

Yang, C. C.

S. Y. Ting, P. J. Chen, H. C. Wang, C. H. Liao, W. M. Chang, Y. P. Hsieh, and C. C. Yang, “Crystallinity improvement of ZnO thin film on different buffer layers grown by MBE,” J. Nanomater. 2012, 6 (2012), doi:.
[Crossref]

Yang, S. M.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

Yano, M.

C. R. Hall, L. V. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, C. Jagadish, and J. A. Davis, “Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field,” Appl. Phys. Lett. 96(19), 193117 (2010).
[Crossref]

V. A. Coleman, M. Buda, H. H. Tan, C. Jagadish, M. R. Phillips, K. Koike, S. Sasa, M. Inoue, and M. Yano, “Observation of blue shifts in ZnO/ZnMgO multiple quantum well structures by ion-implantation induced intermixing,” Semicond. Sci. Technol. 21(3), L25–L28 (2006).
[Crossref]

K. Koike, G. Y. Takada, K. Fujimoto, S. Sasa, M. Inoue, and M. Yano, “Characterization of [ZnO]m[ZnMgO]n multiple quantum wells grown by molecular beam epitaxy,” Physica E 32(1-2), 191–194 (2006).
[Crossref]

K. Koike, I. Nakashima, K. Hashimoto, S. Sasa, M. Inoue, and M. Yano, “Characteristics of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor grown on sapphire substrate by molecular-beam epitaxy,” Appl. Phys. Lett. 87(11), 112106 (2005).
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Yao, T.

J. G. Kim, S. K. Han, S. M. Yang, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. E. Ihm, D. Kim, J. S. Park, H. J. Lee, and T. Yao, “Effects of low temperature ZnO and MgO buffer thicknesses on properties of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy,” Thin Solid Films 519(1), 223–227 (2010).
[Crossref]

H. Kato, K. Miyamoto, M. Sano, and T. Yao, “Polarity control of ZnO on sapphire by varying the MgO buffer layer thickness,” Appl. Phys. Lett. 84(22), 4562–4564 (2004).
[Crossref]

Y. Chen, S. K. Hong, H. J. Ko, V. Kirshner, H. Wenisch, T. Yao, K. Inaba, and Y. Segawa, “Effects of an extremely thin buffer on heteroepitaxy with large lattice mismatch,” Appl. Phys. Lett. 78(21), 3352–3354 (2001).
[Crossref]

Y. Chen, H. J. Ko, S. K. Hong, and T. Yao, “Layer-by-layer growth of ZnO epilayer on Al2O3 (0001) by using a MgO buffer layer,” Appl. Phys. Lett. 76(5), 559–561 (2000).
[Crossref]

D. M. Bagnall, Y. F. Chen, Z. Zhu, T. Yao, S. Koyama, M. Y. Shen, and T. Goto, “Optically pumped lasing of ZnO at room temperature,” Appl. Phys. Lett. 70(17), 2230–2232 (1997).
[Crossref]

Yasuda, T.

T. Makino, Y. Segawa, M. Kawasaki, A. Ohtomo, R. Shiroki, K. Tamura, T. Yasuda, and H. Koinuma, “Band gap engineering based on MgxZn1−xO and CdyZn1−yO ternary alloy films,” Appl. Phys. Lett. 78(9), 1237–1239 (2001).
[Crossref]

A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
[Crossref]

Ye, Z.

K. Wu, H. He, Y. Lu, J. Huang, and Z. Ye, “Dominant free exciton emission in ZnO nanorods,” Nanoscale 4(5), 1701–1706 (2012).
[Crossref] [PubMed]

Ye, Z. Z.

X. Q. Gu, L. P. Zhu, Z. Z. Ye, H. P. He, Y. Z. Zhang, F. Huang, M. X. Qiu, Y. J. Zeng, F. Liu, and W. Jaeger, “Room-temperature photoluminescence from ZnO/ZnMgO multiple quantum wells grown on Si(111) substrates,” Appl. Phys. Lett. 91(2), 022103 (2007).
[Crossref]

Yi, G. C.

W. I. Park, G. C. Yi, and H. M. Jang, “Metalorganic vapor-phase epitaxial growth and photoluminescent properties of Zn1−xMgxO(0 ≤ x ≤ 0.49) thin films,” Appl. Phys. Lett. 79(13), 2022–2024 (2001).
[Crossref]

Yin, J.

E. Francesco Pecora, W. Zhang, A. Yu. Nikiforov, L. Zhou, D. J. Smith, J. Yin, R. Paiella, L. Dal Negro, and T. D. Moustakas, “Sub-250 nm room-temperature optical gain from AlGaN/AlN multiple quantum wells with strong band-structure potential fluctuations,” Appl. Phys. Lett. 100(6), 061111 (2012).
[Crossref]

Yoshida, Y.

A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa, “MgxZn1−xO as a II–VI widegap semiconductor alloy,” Appl. Phys. Lett. 72(19), 2466–2468 (1998).
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Yu. Nikiforov, A.

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Figures (8)

Fig. 1
Fig. 1 Schematic picture for the layer structures of (a) Sample A, (b) Sample B, (c) Sample C, and (d) Sample D, used in this work.
Fig. 2
Fig. 2 (a) XRD ω-2θ spectra, and (b) normalized XRC results of Samples A, B, C, and D.
Fig. 3
Fig. 3 Band diagram of (a) Sample A, and (b) Sample B.
Fig. 4
Fig. 4 PL spectra of samples at 10 K.
Fig. 5
Fig. 5 PL spectra as a function of temperatures of (a) Sample A, (b) Sample B, and (c) Sample C.
Fig. 6
Fig. 6 PL spectra of Sample B, deconvoluted with Gaussian functions at 10 and 75K.
Fig. 7
Fig. 7 The normalized integrated intensity of samples as functions of temperature.
Fig. 8
Fig. 8 (a) HRTEM image of Sample C, (b) Enlarged image of blue dashed line area in (a), and (c) Enlarged image of red dashed line area in (a).

Tables (1)

Tables Icon

Table 1 Peak Position, FWHM, Strain, Stress, Lattice Constant, EDS Mg/Zn Ratio, and Mg Concentrations of the Samples from XRD Measurements

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