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Abstract
Direct epitaxial growth of group III-V light sources with excellently thermal performance on silicon photonics chips promises low-cost, low-power-consumption, high-performance photonic integrated circuits. Here, we report on the achievement of ultra-high thermal stability 1.3 µm InAs/GaAs quantum dot (QD) lasers directly grown on an on-axis Si (001) with a record-high continuous-wave (CW) operating temperature of 150 °C. A GaAs buffer layer with a low threading dislocation density (TDD) of 4.3 × 106 cm-2 was first deposited using an optimized three-step growth method by molecular beam epitaxy. Then, an eight-layer QD laser structure with p-type modulation doping to enhance the temperature stability of the device was subsequently grown on the low TDD Si-based GaAs buffer layer. It is shown that the QD laser exhibits the ultra-high temperature stability with a characteristic temperature T0=∞ and T1=∞ in the wide temperature range of 10-75 °C and 10-140 °C, respectively. Moreover, a maximum CW operating temperature of up to 150 °C and a pulsed operating temperature of up to 160 °C are achieved for the QD laser. In addition, the QD laser shows a high CW saturation power of 50 mW at 85 °C and 19 mW at 125 °C, respectively.
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1. Introduction
Silicon optoelectronics with low cost, low power and high integration have important application prospects in areas such as high-capacity data transmission, high-performance optical computing and high-precision LIDAR [1–4]. Furthermore, on-chip light sources should have excellent high temperature resistance and temperature stability to withstand high operating temperatures close to high heat dissipation complementary metal oxide semiconductor (CMOS) electronic processing units (30 to 150 °C) in applications such as high bandwidth, low latency on-chip optical interconnects [1]. Direct epitaxial group III-V gain materials on CMOS process-compatible on-axis Si (001) substrates are considered to be the most ideal solution for future Si-based photonic integrated circuits (PICs) light sources with lower cost and higher integration [5–7]. Due to its high defect tolerance, quantum dot (QD) material on silicon is a particularly attractive candidate [8–12]. For GaAs-based QD material, 1.3 µm InAs/GaAs QD lasers can achieve high operating temperature up to 220 °C [13], as well as high temperature stability with a characteristic temperature T0=∞ in the range of 15–75 °C [14], and other proven excellent properties such as low threshold current density, high differential gain, and resistance to external optical feedback [15]. Transferring these advantages of QD lasers to silicon substrates is extremely attractive for realizing high performance PICs.
It is well known that the main problem for monolithic integration is the crystal defects resulting from the significant material differences between Group III-V materials and Si substrates. These defects act as non-radiative recombination centers and shunt paths in the fabricated devices, which significantly degrade the device performance, including output power attenuation, narrow operating temperature range, etc [10,16]. In recent years, reports of InAs/GaAs QD lasers on on-axis Si (001) substrates, which benefit from the development of high quality Si-based GaAs buffer layers, have yielded impressive results, including high continuous-wave (CW) operating temperatures of 108 °C, high characteristic temperature T0 of 167 K over 30–60 °C, and high extrapolation lifetimes of over 22 years [17]. Additional improvements in optical noise and anti-reflection are also available [7,18,19]. Furthermore, some new structures of Si-based QD lasers have shown a positive impact on the development of Si-based light sources [20–24]. However, there is still a large gap between the operating temperature range and temperature stability of devices grown directly on silicon and GaAs substrates. Therefore, in order to develop high-performance Si-based chips for more complex application scenarios, it is important to fully exploit the potential of QD lasers on Si (001) substrates and further improve the operating temperature range and temperature stability.
In this paper, we demonstrate ultra-high thermal stability 1.3 µm InAs/GaAs QD lasers with a record-high CW operating temperature of up to 150 °C, directly grown on on-axis Si (001) substrates by molecular beam epitaxy (MBE). An optimized three-step growth method was used to prepare a Si-based GaAs buffer layer material for the growth of subsequent InAs/GaAs QD laser structure, with a low threading dislocation density (TDD) of 4.3 × 106 cm-2. Then, a laser structure with high-quality eight QD layers in its active region was deposited on the low TDD Si-based GaAs buffer layer and p-type modulation doping was applied to enhance the temperature stability of the QD laser [25]. For a ridge-waveguide-type QD laser with a cavity length of 2000µm, the laser exhibits ultra-high temperature stability with a characteristic temperature T0 = ∞ in the wide temperature range of 10 - 75 °C and T1 = ∞ in the range of 10 - 140 °C, respectively. Furthermore, a maximum CW operating temperature of up to 150 °C and a pulsed operating temperature of up to 160 °C for the QD laser are achieved.
2. Experimental procedure
2.1 Crystal growth
A Riber Compact 21 MBE system was used for the growth of GaAs buffer layer and QDs material on an APD-free on-axis GaP/Si (001) template. The complete epitaxial structure is shown in Fig. 1. A 1.6 µm GaAs buffer layer was grown by an improved three-step temperature growth method, where a 30 nm low temperature layer (LT 400–500 °C) was grown, followed by a 70 nm intermediate temperature layer (IT 500–600 °C) and a 1500 nm high temperature layer (HT 600–700 °C). The TDD and surface roughness of the GaAs buffer were measured and calculated by X-ray diffraction (XRD) rocking curve analysis [26] and atomic force microscopy (AFM), respectively. As shown in Fig. 1(b), the full width at half maximum (FWHM) of the GaAs buffer obtained by the conventional two-step temperature growth method (100 nm LT + 1500 nm HT) and the three-step temperature growth method are 182.3 and 173.3 arcsec, respectively. Compared with the two-step method, the TDD of the three-step method decreased by 10.9% from 1.12 × 108 cm-2 to 1.01 × 108 cm-2, and the root-mean-square (RMS) roughness decreased by 24.6% from 2.48 to 1.99 nm within a scanning area of 5 × 5 µm2 (AFM figures not shown here). Thus, the three-step temperature growth method can effectively improve the material quality of GaAs buffers, including the reduction of TDD and surface roughness. To promote dislocation annihilation, dislocation filtration layers and cyclic thermal annealing were employed [27]. Two sets of strained layer superlattices (SLSs) consisting of 10 periods of 10 nm In0.13Ga0.87As/10 nm GaAs were inserted. Subsequently, multiple cycles of thermal annealing were performed to promote dislocation slippage and further reduce the TDD of the GaAs buffer. Finally, TDD and surface roughness were measured on a 3 µm-GaAs-thick buffer layer. The TDD of the GaAs buffer was non-destructively characterized using electronic channel contrast imaging (ECCI), as shown in Fig. 1(c). Calculation of the defects revealed a low TDD of 4.3 × 106 cm-2. Figure 1(d) shows a typical 5 × 5 µm2 AFM image of the GaAs buffer with an RMS roughness of 2.46 nm.
Fig. 1. (a) Schematic diagram of the InAs/GaAs QD laser on on-axis Si (001) substrate. (b) XRDs of the 1.6 µm GaAs buffer layers grown on Si (001) by two-step and three-step temperature growth. (c) ECCI diagram of the 3 µm GaAs buffer interface. (d) AFM image of the 3 µm GaAs buffer interface within a scanning area of 5 × 5 µm2.
The laser structure was then grown on the original GaAs buffer. The active region consists of eight InAs/GaAs QD layers. The self-assembled QDs were directly grown on GaAs and then covered by a 4 nm In0.17Ga0.83As strain-reducing layer and a 45 nm GaAs barrier layer. P-type modulation doping is applied in the 6 nm barrier layer between the QD layers with a concentration of 1 × 1018 cm-3 to achieve higher temperature characteristics, which corresponds to 14 holes per dot [13,25,28]. The QD active region is sandwiched between two 1.4 µm Al0.4Ga0.6As cladding layers. Finally, 300 nm of p-type GaAs is grown on top of the structure as a p-contact layer. For comparison, a laser with only five QD layers in the active region is also grown.
Under the same growth conditions as the laser, we grow the Si-based QD material sample, which consists of an embedded QD layer and a surface QD layer, to characterize the material quality. The optical properties of the material were measured by photoluminescence (PL) from a 532 nm light source. The PL peak wavelength of the QD material is 1305 nm, and the FWHM of the Gaussian fitted PL is 40 meV. Compared with GaAs-based QDs grown under the same conditions, the PL peak intensity of Si-based QDs is about 80% of that of GaAs-based QDs. In addition, the density of Si-based QDs is about 4.3 × 1010 cm-2.
2.2 Device fabrication
Then, the Fabry-Perot (FP) lasers with different cavity lengths of 1000, 1500, and 2000µm and ridge widths of 6, 10, and 30 µm were fabricated using standard photolithography and wet chemical etching techniques. The schematic diagram of the InAs/GaAs QD laser prepared on a silicon substrate and the scanning electron microscope (SEM) cross section images are shown in Fig. 2. Ridge waveguides were formed by etching mesas of different widths on the surface of the active region. Ti/Pt/Au and AuGe/Ni/Au were deposited to form P and N metal electrodes, respectively, after opening the metal contact window on the 350 nm SiO2 electrical isolation layer. The silicon substrate was thinned to ∼100 µm and cleaved into lasers with different cavity lengths. A single cavity surface is then coated with a highly reflective film with 95% reflectance. The lasers are placed on an indium-plated copper radiator and the laser is tested using a probe station.
Fig. 2. (a) Schematic diagram of device structure of FP QD laser. (b) and (c) SEM images of the cross section of a QD laser.
3. Result and discussion
Figure 3 shows the CW power-current-voltage (P-I-V) characteristics of an 8-layer QD laser with a cavity length of 1000 µm and a ridge width of 6 µm at room temperature (RT). The I-V curve shows a series resistance of 4 - 6 Ω. The threshold current of the laser is 56 mA, corresponding to a threshold current density of 933.3 A/cm2. The slope efficiency of the laser reaches 0.22 W/A, and the output light power of the laser reaches nearly 50 mW under the injection current of 300 mA. The inset shows a lasing spectrum of the device at 1.5 times threshold current. The laser emits at 1315.9 nm. The wider ridge waveguide laser should exhibit a lower threshold current density. The threshold current of the 8-layer QD laser is 294.7 mA for a 30 × 1500 µm2 device, and the threshold current density is 654.9 A/cm2, corresponding to only 81.9 A/cm2 per layer. It is close to the results of p-type modulation doped QD lasers grown on on-axis Si (001) reported by other groups [10,17]. The slope efficiency of the laser is 0.2 W/A and the saturation power reaches 91.6 mW.
Fig. 3. CW P–I-V curves of a 6 × 1000 µm2 QD laser. Inset: the emission spectrum of the laser at RT.
Temperature characteristics are one of the most important metrics for evaluating laser performance, and future lasers need to be able to operate continuously with minimal cooling in high-temperature environments such as data centers. Figure 4 shows the change of CW P-I curve with temperature from 10 °C to 150 °C for a 6 × 2000 µm2 QD laser. The 8-layer QD laser has a threshold current of 116.1 mA and an output power of more than 100 mW at 20 °C, and there is no sign of performance degradation even at the injection current of up to 830 mA. Moreover, the laser shows a saturation power of 50 mW at 85 °C and 19 mW at 125 °C, respectively. With further increasing temperature, the saturation output power of the laser still reaches 2.5 mW at 148 °C, but the output power decreases to 0.13 mW at 150 °C. To the best of our knowledge, these results represent the highest O-band CW operating temperatures for any lasers grown directly on Si substrates including 119 °C for offcut silicon [29] and 108 °C for on-axis silicon [17]. Furthermore, it is noteworthy that the QD laser maintains high output light power at high temperatures, which has positive implications for supporting more transmission channels and integrated devices. The high-temperature characteristics of Si-based QD lasers are expected to be further improved by enhancing the uniformity of QD materials, double-sided coating, and hard soldering the laser to a high thermal conductivity heat sink.
Figure 5 shows the CW emission spectra of the same laser at 1.5 times threshold current at each stage temperature from 15 °C to 125 °C and at 400 mA under 140 °C and 145 °C. As can be seen from the figure, the laser always maintains ground state lasing in the above temperature range. The emission wavelength of the laser gradually redshifts from 1313.1 nm at 15 °C to 1345 nm at 85 °C. The wavelength of the laser varies with temperature by 0.456 nm/°C. When the temperature is increased to 95 °C, the laser shows obvious two-mode lasing. The long-wavelength mode dominates as the temperature continues to increase. The peak wavelengths of the laser are 1375 nm at 125 °C and 1377.5 nm at 145 °C, respectively.
To reduce the influence of laser self-heating on the temperature characteristics of the device, we also measured the P-I characteristics of the laser under pulse mode with a pulse-width of 1 µs and a duty-ratio of 1%. Figure 6(a) shows the temperature dependence of the pulsed P-I characteristics of the QD laser for a 6 × 2000 µm2 laser. At 150 °C, the saturation output power of the laser reaches 12.3 mW. The temperature stability of the laser was then measured, and the characteristic temperatures T0 and T1 were calculated using the exponential functions of the threshold current Ith$\propto$exp(T/T0) and the slope efficiency η$\propto$exp(-T/T1). The relationship between the natural logarithm of the threshold current and slope efficiency and temperature is shown in Fig. 6(b). As seen in Fig. 6, in the range of 10–75 °C, the threshold current of the laser basically remains unchanged, and the corresponding characteristic temperature T0 is ∞. This is consistent with the reported highest temperature stability results for GaAs-based QD lasers [14] and is of great value for silicon PICs. In addition, in the range of 85–140 °C, the characteristic temperature T0 of the laser is still as high as 117.4 K, which is also higher than the typical value T0>100 K of undoped GaAs-based and Si-based QD lasers [15,30]. The slope efficiency of the QD laser also maintains high temperature stability, and the characteristic temperature T1 is ∞ in the almost entire measured temperature range of 10–140 °C.
Fig. 6. (a) Temperature-dependent pulsed P–I curves from 10 °C to 160 °C for a 6 × 2000 µm2 Si-based QD lasers. (b) Threshold current and slope efficiency vs temperature corresponding to Fig. 6(a).
The laser with wider ridge waveguide shows a higher pulsed output power. As shown in Fig. 7(a), the pulse output power of the 8-layer QD laser exceeds 25 mW at 150 °C, and is still 2 mW at 160 °C for a 10 × 2000 µm2 device. The performance differences between the 5-layer and 8-layer QD lasers are then compared. It can be seen that the threshold current density per QD layer (90 A/cm2) of the 8-layer QD laser is slightly lower than that (99 A/cm2) of the 5-layer QD laser at 25 °C, indicating that the grown 8-layer stacked layers have excellent material quality. The maximum pulse operating temperature of the 5-layer QD laser is only 120 °C. The 8-layer QD laser also outperforms the 5-layer QD laser in terms of temperature stability. In the temperature range from 15 to 75 °C, the T0 of the 8-layer QD laser is ∞, while that of the 5-layer QD laser is only 142 K. These results suggest that high-quality multilayer QDs can significantly enhance the high-temperature performance of Si-based devices.
Fig. 7. (a) Temperature-dependent pulsed P–I curves from 15 °C to 160 °C for a 10 × 2000 µm2 Si-based 8-layer QD lasers. (b) Threshold current and slope efficiency vs temperature corresponding to Fig. 7(a). (c) Temperature-dependent pulsed P–I curves from 15 °C to 120 °C for a 10 × 2000 µm2 Si-based 5-layer QD lasers. (d) Threshold current and slope efficiency vs temperature corresponding to Fig. 7(c).
Table 1. examines the performance of QD lasers grown directly on on-axis Si (001) templates and presents typical results. Obviously, the maximum operating temperature and temperature stability of the QD laser obtained in our work are among the best values in these QD lasers. The results reported here can be attributed to the combination of low-TDD GaAs buffer layer material, high-gain QD active region, and p-type modulation doping.
Table 1. Research progress of Si(001) substrate preparation of high temperature working 1.3 µm QD laser
4. Conclusion
In conclusion, we have successfully demonstrated ultra-high thermal stability 1.3 µm InAs/GaAs QD lasers directly grown on on-axis Si (001) substrates with a record-high CW operating temperature of up to 150 °C. Using an optimized three-step growth method, we show a high quality GaAs buffer layer with a TDD of 4.3 × 106 cm-2 on Si (001). Then, a p-type modulation doped 8-layer QD laser structure is fabricated on GaAs buffer layer. The QD laser exhibits an RT CW threshold current density of 81.9 A/cm2 per QD layer lasing at ∼1.31 µm. An ultra-high temperature stability QD laser is obtained with a characteristic temperature T0 = ∞ in the temperature range of 10 - 75 °C and T1 = ∞ in the range of 10 - 140 °C, respectively. In addition, a laser with maximum CW operating temperature of up to 150 °C is achieved, accompanied by high saturation powers of 50 mW at 85 °C and 19 mW at 125 °C. Furthermore, the QD laser shows a pulsed operating temperature of 160 °C. We believe that this work demonstrates the great prospect of Si-based direct epitaxial QD lasers in realizing low-power consumption, miniaturization and low-cost silicon photonics chips, which provides a strong driving force for the development of low-cost and high-performance silicon PICs.
Funding
National Natural Science Foundation of China (62035012, 62074143, 62004191).
Disclosures
The authors declare no conflicts of interest.
Data Availability
Data underlying the results presented in this paper may be obtained from the authors upon reasonable request.
References
1. Z. Zhou, X. Ou, Y. Fang, E. Alkhazraji, R. Xu, Y. Wan, and J. E. Bowers, “Prospects and applications of on-chip lasers,” eLight 3(1), 1–25 (2023). [CrossRef]
2. Y. Shi, Y. Zhang, Y. Wan, Y. Yu, Y. Zhang, X. Hu, X. Xiao, H. Xu, L. Zhang, and B. Pan, “Silicon photonics for high-capacity data communications,” Photonics Res. 10(9), A106–A134 (2022). [CrossRef]
3. A. H. Atabaki, S. Moazeni, F. Pavanello, H. Gevorgyan, J. Notaros, L. Alloatti, M. T. Wade, C. Sun, S. A. Kruger, H. Meng, K. Al Qubaisi, I. Wang, B. Zhang, A. Khilo, C. V. Baiocco, M. A. Popovic, V. M. Stojanovic, and R. J. Ram, “Integrating photonics with silicon nanoelectronics for the next generation of systems on a chip,” Nature 556(7701), 349–354 (2018). [CrossRef]
4. Y. Wan, J. Norman, S. Liu, A. Liu, and J. E. Bowers, “Quantum Dot Lasers and Amplifiers on Silicon: Recent Advances and Future Developments,” IEEE Nanotechnology Mag. 15(2), 8–22 (2021). [CrossRef]
5. Z. P. Zhou, B. Yin, and J. Michel, “On-chip light sources for silicon photonics,” Light: Sci. Appl. 4(11), e358 (2015). [CrossRef]
6. J. C. Norman, D. Jung, Y. T. Wan, and J. E. Bowers, “Perspective: The future of quantum dot photonic integrated circuits,” APL Photonics 3(3), 030901 (2018). [CrossRef]
7. F. Grillot, J. C. Norman, J. Duan, Z. Zhang, B. Dong, H. Huang, W. W. Chow, and J. E. Bowers, “Physics and applications of quantum dot lasers for silicon photonics,” Nanophotonics 9(6), 1271–1286 (2020). [CrossRef]
8. S. Chen, W. Li, J. Wu, Q. Jiang, M. Tang, S. Shutts, S. N. Elliott, A. Sobiesierski, A. J. Seeds, I. Ross, P. M. Smowton, and H. Liu, “Electrically pumped continuous-wave III-V quantum dot lasers on silicon,” Nat. Photonics 10(5), 307–311 (2016). [CrossRef]
9. S. Chen, M. Liao, M. Tang, J. Wu, M. Martin, T. Baron, A. Seeds, and H. Liu, “Electrically pumped continuous-wave 1.3 microm InAs/GaAs quantum dot lasers monolithically grown on on-axis Si (001) substrates,” Opt. Express 25(5), 4632–4639 (2017). [CrossRef]
10. 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 mum quantum-dot lasers epitaxially grown on on-axis (001) GaP/Si,” Opt. Lett. 42(2), 338–341 (2017). [CrossRef]
11. J. Kwoen, B. 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]
12. C. Shang, Y. Wan, J. Selvidge, E. Hughes, R. Herrick, K. Mukherjee, J. Duan, F. Grillot, W. W. Chow, and J. E. Bowers, “Perspectives on Advances in Quantum Dot Lasers and Integration with Si Photonic Integrated Circuits,” ACS Photonics 8(9), 2555–2566 (2021). [CrossRef]
13. T. Kageyama, K. Nishi, M. Yamaguchi, R. Machida, Y. Maeda, K. Takemasa, Y. Tanaka, T. Yamamoto, M. Sugawara, and Y. Arakawa, “Extremely high temperature (220 °C) continuous-wave operation of 1300-nm range quantum-dot lasers,” in CLEO/Europe and EQEC 2011 Conference Digest (Optical Society of America, 2011).
14. S. Fathpour, Z. Mi, P. Bhattacharya, A. R. Kovsh, S. S. Mikhrin, I. L. Krestnikov, A. V. Kozhukhov, and N. N. Ledentsov, “The role of Auger recombination in the temperature-dependent output characteristics (T0=∞) of p-doped 1.3 µm quantum dot lasers,” Appl. Phys. Lett. 85(22), 5164–5166 (2004). [CrossRef]
15. A. E. Zhukov, M. V. Maksimov, and A. R. Kovsh, “Device characteristics of long-wavelength lasers based on self-organized quantum dots,” Semiconductors 46(10), 1225–1250 (2012). [CrossRef]
16. S. Shutts, C. P. Allford, C. Spinnler, Z. Li, A. Sobiesierski, M. Tang, H. Liu, and P. M. Smowton, “Degradation of III-V Quantum Dot Lasers Grown Directly on Silicon Substrates,” IEEE J. Select. Topics Quantum Electron. 25(6), 1–6 (2019). [CrossRef]
17. C. Shang, E. Hughes, Y. 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]
18. J. Duan, Y. Zhou, B. Dong, H. Huang, J. C. Norman, D. Jung, Z. Zhang, C. Wang, J. E. Bowers, and F. Grillot, “Effect of p-doping on the intensity noise of epitaxial quantum dot lasers on silicon,” Opt. Lett. 45(17), 4887–4890 (2020). [CrossRef]
19. J. J. Chen, Z. H. Wang, W. Q. Wei, T. Wang, and J. J. Zhang, “Sole Excited-State InAs Quantum Dot Laser on Silicon With Strong Feedback Resistance,” Front. Mater. 8, 648049 (2021). [CrossRef]
20. Y. Wan, J. Norman, Q. Li, M. J. Kennedy, D. Liang, C. Zhang, D. Huang, Z. Zhang, A. Y. Liu, A. Torres, D. Jung, A. C. Gossard, E. L. Hu, K. M. Lau, and J. E. Bowers, “1.3 µm submilliamp threshold quantum dot micro-lasers on Si,” Optica 4(8), 940–944 (2017). [CrossRef]
21. 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]
22. Y. Wan, S. Zhang, J. C. Norman, M. J. Kennedy, W. He, S. Liu, C. Xiang, C. Shang, J. J. He, A. C. Gossard, and J. E. Bowers, “Tunable quantum dot lasers grown directly on silicon,” Optica 6(11), 1394–1400 (2019). [CrossRef]
23. T. Zhou, M. Tang, G. Xiang, B. Xiang, S. Hark, M. Martin, T. Baron, S. Pan, J. S. Park, Z. Liu, S. Chen, Z. Zhang, and H. Liu, “Continuous-wave quantum dot photonic crystal lasers grown on on-axis Si (001),” Nat. Commun. 11(1), 977 (2020). [CrossRef]
24. Y. Wan, C. Xiang, J. Guo, R. Koscica, M. Kennedy, J. Selvidge, Z. Zhang, L. Chang, W. Xie, D. Huang, A. C. Gossard, and J. E. Bowers, “High Speed Evanescent Quantum-Dot Lasers on Si,” Laser Photonics Rev. 15(8), 2100057 (2021). [CrossRef]
25. O. B. Shchekin and D. G. Deppe, “1.3 µm InAs quantum dot laser with T0=161 K from 0 to 80 °C,” Appl. Phys. Lett. 80(18), 3277–3279 (2002). [CrossRef]
26. Y. Wang, B. Ma, J. Li, Z. Liu, C. Jiang, C. Li, H. Liu, Y. Zhang, Y. Zhang, Q. Wang, X. Xie, X. Qiu, X. Ren, and X. Wei, “InAs/GaAs quantum-dot lasers grown on on-axis Si (001) without dislocation filter layers,” Opt. Express 31(3), 4862–4872 (2023). [CrossRef]
27. D. Jung, J. Norman, M. J. Kennedy, C. Shang, B. Shin, Y. Wan, A. C. Gossard, and J. E. Bowers, “High efficiency low threshold current 1.3 µm InAs quantum dot lasers on on-axis (001) GaP/Si,” Appl. Phys. Lett. 111(12), 122107 (2017). [CrossRef]
28. D. G. Deppe, H. Huang, and O. B. Shchekin, “Modulation characteristics of quantum-dot lasers: The influence of P-type doping and the electronic density of states on obtaining high speed,” IEEE J. Quantum Electron. 38(12), 1587–1593 (2002). [CrossRef]
29. A. Y. Liu, C. Zhang, J. Norman, A. Snyder, D. Lubyshev, J. M. Fastenau, A. W. K. Liu, A. C. Gossard, and J. E. Bowers, “High performance continuous wave 1.3 µm quantum dot lasers on silicon,” Appl. Phys. Lett. 104(4), 041104 (2014). [CrossRef]
30. 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. Sel. Top. Quantum Electron. 26(2), 1–9 (2020). [CrossRef]
31. 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]
32. D. Jung, Z. Zhang, J. Norman, R. Herrick, M. J. Kennedy, P. Patel, K. Turnlund, C. Jan, Y. 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]
33. 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]
34. C. Shang, K. Feng, E. T. Hughes, A. Clark, M. Debnath, R. Koscica, G. Leake, J. Herman, D. Harame, P. Ludewig, Y. Wan, and J. E. Bowers, “Electrically pumped quantum-dot lasers grown on 300 mm patterned Si photonic wafers,” Light: Sci. Appl. 11(1), 299 (2022). [CrossRef]
