Open Access
Add to BibSonomy
Abstract
We report electrically pumped continuous-wave (CW) InAs/GaAs quantum dot lasers directly grown on planar exact silicon (001) with asymmetric waveguide structures. Surface hydrogen-annealing for the GaAs/ Si (001) templates and low-temperature growth for GaInP upper cladding layers were combined in the growth of the laser structure to achieve a high slope efficiency. For the broad-stripe edge-emitting lasers with 2-mm cavity length and 20-µm stripe width made from the above laser structure, a threshold current density of 203.5 A/cm2 and a single-facet slope efficiency of 0.158 W/A are achieved at ∼1.31 µm band under CW conditions. The extrapolated mean-time-to-failure reaches up to 21000 hours at room temperature, which is deduced from the data measured from C-mount packaged devices. Importantly, these results can provide a practical strategy to realize 1.3 µm wavelength band distributed feedback lasers directly on planar exact Si (001) templates with thin buffer layers.
© 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
1. Introduction
Optical modules have been facing great challenges and opportunities in chip size, transmission speed and power assumption with the rapid development of global information transmission and processing, especially in data center applications [1,2]. Optoelectronic monolithic integration combining mature silicon process and high-speed, low-power consumption photonic devices on silicon platform is promising to solve the bottleneck problem in the near future owning to advantages of complementary metal-oxide-semiconductor (COMS) integration and photonic technology [3,4]. Currently, the monolithic integration on silicon is reaching maturity for a majority of photonic devices except for integrated lasers. The quantum dot lasers directly grown on silicon have attracted increasing attention due to their impressive performances and the reported monolithic integrated III-V lasers on silicon with lifetime of more than 100 thousand hours [5,6]. It should be highlighted that the direct growth of quantum dot lasers on microelectronics-standard exact (001) Si substrates is a prerequisite for the integrated lasers due to the integration requirements of process compatibility with COMS technology [7–9]. For lasers directly grown on exact (001) Si, two main approaches have to be addressed. The first one relates to the lasers grown on planar exact (001) silicon (with miscut angle less than 0.5°) [7–10], and the second one involves to the lasers grown on patterning silicon substrates [11–13]. Moreover, the former one has been attracting extensive scientific and industrial interest as it can offer a low-cost solution for silicon monolithic photonic integration [14].
Up to date, several research groups have made great progress on 1.3 µm wavelength quantum dot (QD) lasers directly grown on planar exact silicon (001) substrates. In 2017, Liu et al. [7] demonstrated continuous-wave (CW) 1.3 µm InAs QD lasers with a slope efficiency of 0.08 W/A, in which adopted GaP/Si (001) templates commercially provided by NAsP III–V GmbH [15]. Chen et al. [9] reported 1.3 µm InAs QD lasers directly grown on GaAs/Si (001) templates, which utilized the hydrogen-annealing process [16,17], a thick GaAs buffer layer and defect filter layers (totally 3 µm). It achieved a threshold current density of 425 A/cm2 and a slope efficiency of 0.068 W/A under CW operation at room temperature.
In 2018, Kwoen et al. [10,18] developed a 1.3 µm InAs QD lasers on exact Si (001) with a threshold current density of 370 A/cm2 and a slope efficiency of 0.053 W/A under CW operation at room temperature, in which a 40 nm-thick AlGaAs buffer layer was applied to promote antiphase domain (APD) annihilation, together with a thick GaAs buffer layer and defect filter layers (DFLs, totally 2.7 µm).
In 2020, Wan et al. [14] adopted hydrogen-annealing process to suppress APD formation, a thick GaAs buffer layer and DFLs (totally 3.1 µm) to reduce dislocation. The threshold current density and the slope efficiency reach up to 173 A/cm2 and 0.153 W/A, respectively. Li et al. [19] reported 1.3 µm InAs QD lasers directly grown on exact Si (001) substrates via using Si buffer layer and thermal annealing to promote APD annihilation, and with thick buffer layers and DFLs (totally 2.4 µm). They obtained a threshold current density of 83.3 A/cm2 and a slope efficiency of 0.13 W/A under CW operation at room temperature.
It is worth noting that all these QD laser structures on planar exact Si (001) templates, including both lower and upper AlGaAs cladding layers as well as QD active regions, were symmetric waveguide structures and grown by molecular beam epitaxy (MBE) technology [7–11,13,14,18,19]. MBE is the most suitable technology for high quality QD growth, but has three disadvantages for lasers grown on planar exact Si (001) substrates. Firstly, MBE cannot perform the hydrogen-annealing process to suppress APDs of III-Vs on exact Si (001) substrates due to the absence of hydrogen atmosphere [19]. Also, the growth of phosphorus-contain materials is difficult, such as GaInP [20]. Moreover, the quality of regrowth or selective area growth is poor, which is important in fabrication of distributed feedback (DFB) lasers, and optical integrated structures [21,22]. While, the above three issues can be well settled via metalorganic chemical vapor deposition (MOCVD) technology. In our earlier work of QD lasers on Si which were grown by all MOCVD [23], the room-temperature lasing wavelength at ∼1.3 µm was achieved with a threshold density of 737 A/cm2 and a slope efficiency of 0.028 W/A under CW operation. Obviously, the quality of QDs grown by MOCVD was worse than that grown by MBE, which resulted in high threshold current density and very low slope efficiency for the QD lasers. In addition, a thin buffer layer is very necessary for optical coupling of the silicon integrated light sources to a Si photonic integration chip.
To further improve the slope efficiency of the QD laser on Si, we propose to grow exact Si (001) templates and GaInP upper cladding layer via MOCVD [23,24], but the QD active region by MBE. This strategy combines the merits of MBE and MOCVD, and can improve performance of our QD lasers on Si significantly: (1) the thermal hydrogen-annealing process is adopted to suppress APDs and thin the buffer layers of GaAs/Si (001) templates, (2) an asymmetric waveguide structure is well suited for single-mode lasers with high slope efficiency and high power in silicon integration applications [25,26], (3) the growth temperature of GaInP cladding layer is greatly reduced to 560 °C by MOCVD, which is even lower than that of AlGaAs cladding layer by MBE. Hence, the degradation of QD quality during postgrowth of upper cladding layers can be completely ignored. Using this strategy, we developed 1.3 µm band InAs QD lasers with asymmetric waveguide structure grown on planar exact Si (001) substrates. The broad-stripe edge-emitting lasers with 2-mm cavity length and 20-µm stripe width were fabricated. The devices lasing at ∼1310 nm with threshold density of 203.5 A/cm2 and slope efficiency of 0.158 W/A are achieved under CW condition at room temperature. A single-facet output power of 63.9 mW is obtained at the injection current of 500 mA. The extrapolated mean-time-to-failure is 1149 hours at 85 °C and more than 21000 hours at room temperature for the C-mount package lasers.
2. Material growth and device fabrication
The designed epitaxial structure of 1.3 µm InAs QD lasers on exact Si (001) was shown in Fig. 1(a). The whole structure growth mainly includes three processes: 1) First, 420-nm APD-free GaAs buffers were grown on exact Si (001) by MOCVD technology as silicon templates. 2) Then, a DFL, n-AlGaAs lower cladding layer and QD active region were grown sequentially by MBE technology. 3) Finally, a p-GaInP upper cladding layer and a GaAs contact layer were grown by MOCVD technology again.
Fig. 1. (a) Schematic of the QD laser structure on exact Si (001) substrates with asymmetric waveguide structure grown by both MOCVD and MBE technologies. (b) 10µm×10µm AFM image of 420 nm GaAs buffers grown on exact Si (001) substrates with a root mean square roughness of 0.99 nm. (c) Room-temperature photoluminescence spectrum of the QD active region grown on the Si template, and the inset is 1×1 µm2 AFM image of uncapped InAs QDs with the QD density of 4.6×1010 cm−2.
For the first growth, the GaAs/Si(001) templates were carried out in an Aixtron-CCS MOCVD system. High-purity trimethylgallium (TMGa), trimethylindium (TMIn), arsine (AsH3), phosphine (PH3) and diethylzinc (DEZn) were used as source materials. The carrier gas was Pd-cell purified hydrogen. All silicon substrates are 2-inch on-axis Si (001) substrates with miscut angles of about 0.37° toward [110] direction. The substrate contaminants including residual organic matter, metal, ionic and surface oxide layer were removed by RCA chemical cleaning. Then the substrates were put into the growth chamber for surface hydrogen-annealing treatment. After annealing treatment, a three-step method was used to grow 420 nm GaAs buffers on Si (001). The specific growth process of suppressing APDs can reference our previous work [24]. The surface morphology of GaAs/Si (001) templates was measured by atomic force microscopy (AFM), as shown in Fig. 1(b). Clearly, there is no APD on the sample surface, and the root mean square roughness is 0.99 nm (10µm×10µm). The results are in accordance with the literature of using the SiConiTM technique for surface treatment process [16]. Since no GaP or Ge buffer layers is required, the totally thin buffer layers can be allowed in the subsequent growth.
For the second growth, a 300 nm GaAs layer was grown on GaAs/Si (001) template by a solid-source MBE, followed by three-repeats of 10nm In0.15Ga0.85As/10nm GaAs strained layer superlattices (SLSs) separated by 300 nm GaAs spacing layers to serve as DFLs. For the last repeat, the GaAs spacing layer is 100 nm, and no thermal cycle annealing was employed. The dislocation density was below 1.0×108 cm−2 estimated by the cross-sectional transmission electron microscopy. Subsequently, a 500 nm n-type GaAs contact layer and 1.4 µm lower n-Al0.4Ga0.6As cladding layer were grown with doped concentration of 4×1018cm−3 and 0.5∼1.0×1018 cm−3 respectively. For comparison, the same laser structure begin with n-GaAs contact layer was also grown on a semi-insulating (SI) GaAs substrate. Then, a 60 nm undoped GaAs layer and a five-layer InAs/InGaAs/GaAs dot-in-well (DWELL) laser active region was separated by 40 nm GaAs spacer layers. For QD layers, the growth temperature (measured by thermocouple), growth rate and V/III ratio were 560 °C, ∼0.06 ML/s and 20, respectively. For the GaAs spacer layers, the growth temperature is 675 °C. A typical 1×1 µm2 AFM image of the uncapped QDs is shown in the inset of Fig. 1(c), and the QD density is about 4.6×1010 cm−2. For the room-temperature photoluminescence (PL) spectrum of the sample, the peak wavelength and full-width at half-maximum (FWHM) are 1299.6 nm and 30.5 meV, as shown in Fig. 1(c). For comparison, the average PL intensity of the QDs grown on Si is 69% of that grown on native substrates.
For the third growth, a 1.3-µm p-GaInP upper cladding layer with gradient doping concentration of 0.5∼1.0×1018 cm−3 and a 300-nm p+-GaAs layer with doped concentration of about 2×1019 cm−3 as the p-side contact layer were grown by MOCVD again. The growth temperature of the both layers was 560 °C. The detail process can be referred to our previous report [23]. Benefiting from the low growth temperature of GaInP cladding layer, the crystalline quality and optical property of the QD active region have not been influenced. Further, the refractive index of GaInP upper cladding layer is smaller than that of Al0.4Ga0.6As lower cladding layer, and it forms an asymmetric waveguide structure. Hence, the field intensity profile of the fundamental-transverse mode shifts properly to the n-type side, and thus reducing the field overlap with the p-cladding layer, as shown in Fig. 2. It can decrease the internal loss and enhance the slope efficiency of laser devices [25,26].
Fig. 2. Vertical waveguide structure and calculated near-field intensity distribution of the fundamental-transverse mode for emission wavelength of 1.3 µm.
A schematic of the chip structure of the edge-emitting broad-stripe lasers is shown in Fig. 3(a). The stripe width and cavity length are 20 µm and 2 mm for a single chip. The laser facets were formed by cleaving with no facets optical coating. For comparison, the cross-sectional scanning electron microscope (SEM) image of a device structure is also shown in Fig. 3(b). The detailed fabrication processes were properly modified based on our previous report [23,27]. Then the devices were mounted on copper heatsinks (C-mount package) and their performance were carried out under CW conditions.
Fig. 3. (a) Schematic of the device structure. (b) Cross-sectional SEM image of the part of a device structure.
3. Result and discussion
Figure 4 shows light-current-voltage (L-I-V) characteristics measured under CW condition at room temperature (25 °C) for 2 mm×20 µm broad-stripe lasers grown on Si and GaAs substrates. For the laser on Si, the threshold current is 81.4 mA corresponding to a threshold current density of 203.5 A/cm2. When the injection current is 500 mA, the single-facet output power and the slope efficiency are 63.9 mW and 0.158 W/A, respectively. For the laser on GaAs substrates, the threshold current is 53.3 mA corresponding to a threshold current density of 133.3 A/cm2. A single-facet output power of 83.8 mW and a slope efficiency of 0.194 W/A are obtained at the injection current of 500 mA. Apparently, the threshold current and the slope efficiency of the former are 1.53 times and 81.4% of the latter, respectively. Statistically, for the lasers on Si, the threshold current was varied from 81.4 to 101.0 mA for seven 2 mm×20 µm devices, and varied from 51.3 to 56.1 mA for six 1 mm×20 µm devices. The threshold current densities increase for shorter cavities. The lasing emission spectra of the laser on Si operated at different injection currents under CW condition are shown in Fig. 5. When the current increases from 80 to 240 mA, the emission wavelength increases gradually. For the injection current of 240 mA, the emission wavelength is 1311.6 nm with a linewidth (FWHM) of 2.7 nm. The typical CW characteristic temperature T0 of the devices is 87 K, calculated from the threshold currents under 25 °C and 85 °C.
Fig. 4. Typical (L-I-V) characteristics of broad-stripe lasers on Si and GaAs substrates respectively measured under CW condition at room temperature.
Fig. 5. Emission spectra for the QD laser on Si (001) at various injection current at room temperature.
The performance comparison of lasers between our previous report [23] and this work is shown in Fig. 6. Both of laser structures consist of an AlGaAs lower cladding layer and a GaInP upper cladding layer. The latter was asymmetric waveguide structure and the QD active region was grown by MBE. The former was symmetric waveguide structure and the whole laser structure is grown by MOCVD. It can be seen, the latter threshold current is decreased by 3.6 times, and the slope efficiency is increased by 5.6 times, respectively. The results demonstrate that a significant improvement achieves in contrast to our previous work. We believe that the quality of the QD active region grown by MBE is much higher than that that of grown by MOCVD, which has much larger optical gain.
The lasers on Si without facets coating in C-mount package were aging at 85 °C under a constant current of 400 mA, which is about 5 times of the initial threshold current. L-I-V measurements were performed periodically (once a week) to monitor the degradation rate during the aging process. Figure 7 displays gradual increases in the threshold current of a typical device for about 1000 hours. The extrapolated mean-time-to-failure (time to double initial threshold current) is 1149 hours at 85 °C and more than 21000 hours at room temperature (25 °C) for conservatively estimated activation energy of 0.45 eV [6,28,29]. The lifetime results demonstrate a relatively ideal reliability for QD lasers directly grown on exact Si (001).
To make a better comparison with the recent progress in this subject, a careful survey on the performances of state-of-the-art QD lasers directly grown on planar exact Si (001) templates was investigated in Table 1, which presents the typical results in buffer layer thickness, slope efficiency and waveguide type for the laser devices reported since 2017. Obviously, the slope efficiency of the laser (with the same and shorter cavity length) achieved in our work is one of the best values among these state-of-the-art QD lasers, and it is the only one using asymmetric waveguide structure for QD lasers directly grown on Si. Consequently, it is favorable for adjusting the field intensity profile in both sides of active regions and coupling the laser beam with silicon waveguides. Furthermore, the laser material with aluminum-free GaInP upper cladding layer and MOCVD growth method is more suitable for DFB lasers on Si with regrowth process.
Table 1. Performance of Different QD Lasers on Exact Si (001) Templates
4. Conclusion
In conclusion, we have demonstrated high slope-efficiency 1.3 µm wavelength band InAs QD lasers directly grown on silicon (001) with asymmetric waveguide structures. Surface hydrogen-annealing for the GaAs/Si (001) templates and low-temperature growth for GaInP upper cladding layers were combined to achieve one of the highest slope efficiency. The broad-stripe edge-emitting lasers with 2-mm cavity length and 20-µm stripe width were fabricated and characterized. The devices exhibited CW lasing at ∼1.31 µm with a threshold density of 203.5 A/cm2 and a slope efficiency of 0.158 W/A. For the C-mount package devices, the extrapolated mean-time-to-failure is 1149 hours at 85 °C and more than 21000 hours at room temperature. These results provide a practical strategy of growing 1.3 µm wavelength band QD lasers directly on exact Si (001), and thus achieving high quality integrated DFB lasers with regrowth process in GaInP upper cladding layers. This strategy is scheduled for fabrication of 1.3 µm band QD DFB lasers on exact Si (001) with high output power in our laboratory. More importantly, with further progress in growth processes on silicon-on-insulators, these Si-based QD lasers with asymmetric waveguide structures could easily realize optical coupling with silicon waveguides, which will significantly promote the commercial development of integrated laser sources in silicon photonics.
Funding
National Key Research and Development Program of China (2018YFB2200104); National Natural Science Foundation of China (61874148); Beijing Municipal Science and Technology Commission (Z191100004819012); Beijing Municipal Natural Science Foundation (4212055); Science Fund for Creative Research Groups (62021005); 111 Project (BP0719012).
Acknowledgments
The authors would like to thank Prof. Huiyun Liu and Dr. Mingchu Tang of University College London for helpful discussion.
Disclosures
The authors declare no conflicts of interest.
Data availability
Data underlying the results presented in this paper are not publicly available at this time but may be obtained from the authors upon reasonable request.
References
1. K. Giewont, K. Nummy, F. A. Anderson, J. Ayala, T. Barwicz, Y. S. Bian, K. K. Dezfulian, D. M. Gill, T. Houghton, S. Hu, B. Peng, M. Rakowski, S. Rauch, J. C. Rosenberg, A. Sahin, I. Stobert, and A. Stricker, “300-mm monolithic silicon photonics foundry technology,” IEEE J. Sel. Top. Quantum Electron. 25(5), 1–11 (2019). [CrossRef]
2. A. H. Safavi-Naeini, D. V. Thourhout, R. Baets, and R. V. Laer, “Controlling phonons and photons at the wavelength scale: integrated photonics meets integrated phononics,” Optica. 6(2), 213–232 (2019). [CrossRef]
3. N. Margalit, C. Xiang, S. M. Bowers, A. Bjorlin, B. Alexis, B. Robert, and J. E. Bowers, “Perspective on the future of silicon photonics and electronics,” Appl. Phys. Lett. 118(22), 220501 (2021). [CrossRef]
4. Z. Zhou, Z. Tu, T. Li, and X. Wang, “Silicon photonics for advanced optical interconnections,” J. Lightwave Technol. 33(4), 928–933 (2015). [CrossRef]
5. S. Chen, W. Li, J. Wu, Q. Jiang, M. Tang, S. Shutts, S. Elliott, A. Sobiesierski, A. Seeds, I. Ross, P. Smowton, and H. Liu, “Electrically pumped continuous-wave III–V quantum dot lasers on silicon,” Nat. Photonics. 10(5), 307–311 (2016). [CrossRef]
6. D. Jung, Z. Zhang, J. Norman, R. Herrick, M. J. Kennedy, P. Patel, K. Turnlund, C. Jan, Y. T. Wan, A. C. Gossard, and J. E. Bowers, “Highly reliable low-threshold InAs quantum dot lasers on on-axis (001) Si with 87% injection efficiency,” ACS Photonics 5(3), 1094–1100 (2018). [CrossRef]
7. A. Y. Liu, J. Peters, X. Huang, D. Jung, J. Norman, M. L. Lee, A. C. Gossard, and J. E. Bowers, “Electrically pumped continuous-wave 1.3 µm quantum-dot lasers epitaxially grown on on-axis (001) GaP/Si,” Opt. Lett. 42(2), 338–341 (2017). [CrossRef]
8. D. Jung, J. Norman, M. J. Kennedy, C. Shang, B. Shin, Y. T. Wan, A. C. Gossard, and J. E. Bowers, “High efficiency low threshold current 1.3 um InAs quantum dot lasers on on-axis (001) GaP/Si,” Appl. Phys. Lett. 111(12), 122107 (2017). [CrossRef]
9. S. Chen, M. Liao, M. C. Tang, J. Wu, M. Martin, T. Baron, A. Seeds, and H. Y. Liu, “Electrically pumped continuous-wave 1.3 µm InAs/GaAs quantum dot lasers monolithically grown on on-axis Si (001) substrates,” Opt. Express 25(5), 4632–4639 (2017). [CrossRef]
10. J. Kwoen, B. Y. Jang, J. Lee, T. Kageyama, K. Watanabe, and Y. Arakawa, “All MBE grown InAs/GaAs quantum dot lasers on on-axis Si (001),” Opt. Express 26(9), 11568–11576 (2018). [CrossRef]
11. J. Norman, M. J. Kennedy, J. Selvidge, Q. Li, Y. Wan, A. Y. Liu, P. G. Callahan, M. P. Echlin, T. M. Pollock, K. M. Lau, A. C. Gossard, and J. E. Bowers, “Electrically pumped continuous wave quantum dot lasers epitaxially grown on patterned, on-axis (001) Si,” Opt. Express 25(4), 3927–3934 (2017). [CrossRef]
12. Y. Xue, W. Luo, S. Zhu, L. Y. Lin, B. Shi, and K. M. Lau, “1.55 µm electrically pumped continuous wave lasing of quantum dash lasers grown on silicon,” Opt. Express 28(12), 18172–18179 (2020). [CrossRef]
13. W. Q. Wei, Q. Feng, J. J. Guo, M. C. Guo, J. H. Wang, Z. H. Wang, T. Wang, and J. J. Zhang, “InAs/GaAs quantum dot narrow ridge lasers epitaxially grown on SOI substrates for silicon photonic integration,” Opt. Express 28(18), 26555–26563 (2020). [CrossRef]
14. Y. T. Wan, C. Shang, J. Norman, B. Shi, Q. Li, N. Collins, M. Dumont, K. M. Lau, A. C. Gossard, and J. E. Bowers, “Low threshold quantum dot lasers directly grown on unpatterned quasi-nominal (001) Si,” IEEE J. Quantum Electron. 26(2), 1–9 (2020). [CrossRef]
15. K. Volz, A. Beyer, W. Witte, J. Ohlmann, I. Nemeth, B. Kunert, and W. Stolz, “GaP-nucleation on exact Si (0 01) substrates for III/V device integration,” J. Cryst. Growth 315(1), 37–47 (2011). [CrossRef]
16. R. Alcotte, M. Martin, J. Moeyaert, R. Cipro, S. David, F. Bassani, F. Ducroquet, Y. Bogumilowicz, E. Sanchez, Z. Ye, X. Bao, J. Pin, and T. Baron, “Epitaxial growth of antiphase boundary free GaAs layer on 300 mm Si(001) substrate by metalorganic chemical vapour deposition with high mobility,” APL Mater. 4(4), 046101 (2016). [CrossRef]
17. M. Martin, D. Caliste, R. Alcotte, J. Moeyaert, S. David, F. Bassani, T. Cerba, Y. Bogumilowicz, E. Sanchez, Z. Ye, X. Y. Bao, J. B. Pin, T. Baron, and P. Pochet, “Toward the III–V/Si co-integration by controlling the biatomic steps on hydrogenated Si (001),” Appl. Phys. Lett. 109(25), 253103 (2016). [CrossRef]
18. J. Kwoen, B. Jang, K. Watanabe, and Y. Arakawa, “High-temperature continuous-wave operation of directly grown InAs/GaAs quantum dot lasers on on-axis Si (001),” Opt. Express 27(3), 2681–2688 (2019). [CrossRef]
19. K. S. Li, J. J. Yang, Y. Lu, M. C. Tang, P. Jurczak, Z. Z. Liu, X. Z. Yu, J. S. Park, H. W. Deng, H. Jia, M. Y. Dang, A. M. Sanchez, R. Beanland, W. Li, X. D. Han, J. C. Zhang, H. Wang, F. Q. Liu, S. M. Chen, A. Seeds, P. Smowton, and H. Y. Liu, “Inversion boundary annihilation in GaAs monolithically grown on on-axis silicon (001),” Adv. Optical Mater. 8(22), 2000970 (2020). [CrossRef]
20. M. Weyers, A. Bhattacharaya, F. Bugge, and A. Knauer, “Epitaxy of high-power diode laser structures,” in High-power diode lasers: fundamentals, technology, applicationsR. Diehl, eds. (Springer-Verlag, Berlin, 2000), pp. 94.
21. Y. Wan, J. C. Norman, Y. Tong, M. J. Kennedy, W. He, J. Selvidge, C. Shang, M. Dumont, A. Malik, H. K. Tsang, A. C. Gossard, and J. E. Bowers, “1.3 µm quantum dot-distributed feedback lasers directly grown on (001) Si,” Laser photonics Rev. 14(7), 2000037 (2020). [CrossRef]
22. Y. Wang, S. Chen, Y. Yu, L. Zhou, L. Liu, C. Yang, M. Liao, M. Tang, Z. Liu, J. Wu, W. Li, I. Ross, A. J. Seeds, H. Liu, and S. Yu, “Monolithic quantum-dot distributed feedback laser array on silicon,” Optica 5(5), 528–533 (2018). [CrossRef]
23. J. Wang, H. Y. Hu, H. Y. Yin, Y. M. Bai, J. Li, Y. Y. Liu, Y. Q. Huang, X. M. Ren, and H. Y. Liu, “1.3 µm InAs/GaAs quantum dot lasers on silicon with GaInP upper cladding layers,” Photonics Res. 6(4), 321–325 (2018). [CrossRef]
24. W. R. Chen, J. Wang, L. N. Zhu, G. F. Wu, Y. Q. Yang, C. Y. Xiao, J. C. Li, H. J. Wang, Y. X. Jia, Y. Q. Huang, and X. M. Ren, “Theoretical and experimental study on epitaxial growth of antiphase boundary free GaAs on hydrogenated on-axis Si (001) surfaces,” J. Phys. D: Appl. Phys. 54(44), 445102 (2021). [CrossRef]
25. Y. Yamagata, Y. Yamada, M. Muto, S. Sato, R. Nogawa, A. Sakamoto, and M. Yamaguchi, “915 nm High power broad area laser diodes with ultra-small optical confinement based on asymmetric decoupled confinement heterostructure (ADCH),” Proceedings of the SPIE. 9348, 93480F (2015). [CrossRef]
26. B. Sumpf, M. Zorn, R. Staske, J. Fricke, P. Ressel, G. Erbert, M. Weyers, and G. Tränkle, “5-W reliable operation over 2000h of 5-mm-wide 650-nm AlGaInP-GaInP-AlGaAs laser bars with asymmetric cladding layers,” IEEE Photonics Technol. Lett. 18(18), 1955–1957 (2006). [CrossRef]
27. J. Wang, X. M. Ren, C. Deng, H. Y. Hu, Y. R. He, Z. Cheng, H. Y. Ma, Q. Wang, Y. Q. Huang, X. F. Duan, and X. Yan, “Extremely low-threshold current density InGaAs/AlGaAs quantum-well lasers on silicon,” J. Lightwave Technol. 33(15), 3163–3169 (2015). [CrossRef]
28. C. Shang, E. Hughes, Y. T. Wan, M. Dumont, R. Koscica, J. Selvidge, R. Herrick, A. C. Gossard, K. Mukherjee, and J. E. Bowers, “High-temperature reliable quantum-dot lasers on Si with misfit and threading dislocation filters,” Optica 8(5), 749–754 (2021). [CrossRef]
29. A. Y. Liu, R. W. Herrick, O. Ueda, P. M. Petroff, A. C. Gossard, and J. E. Bowers, “Reliability of InAs/GaAs quantum dot lasers epitaxially grown on silicon,” IEEE J. Sel. Top. Quantum Electron. 21(6), 690–697 (2015). [CrossRef]
