An InGaSb/A1GaAsSb compressively strained quantum well laser emitting at 2 #m has been fabricated. An output power of 82.2 mW was obtained in continuous wave （CW） mode at room temperature. The laser can operate at high temperature （T = 80 °C）, with a maximum output power of 63.7 mW in CW mode.
报道了激射波长为2.1μm的Ga In Sb/Al Ga As Sb双量子阱激光器。通过优化外延结构设计和欧姆接触,无镀膜的宽条激光器达到了9.8%的峰值功率转换效率,这比原来的值提高了1.5倍,室温下得到了615 m W的连续激射功率输出和1.5 W的脉冲激射功率输出。这些激光器的阈值电流密度低至126 A/cm2,斜率效率高达0.3 W/A。通过测试不同腔长的激光器,测得内损耗和内量子效率分别为6 cm-1和75.5%,均比原有器件有很大提升。激光器在连续工作3 000 h后,功率没有明显下降。
This paper presents a theoretical study on the electrical and optical properties of mid-infrared type-II InAs/GaSb superlattices with different beryllium concentrations in the InAs layer of the active region. Dark current, resistancearea product, absorption coefficient and quantum efficiency characteristics are thoroughly examined. The superlattice is residually n-type and it becomes slightly p-type by varying beryllium-doping concentrations, which improves its electrical performances. The optical performances remain almost unaffected with relatively low p-doping levels and begin to deteriorate with increasing p-doping density. To make a compromise between the electrical and optical performances, the photodetector with a doping concentration of 3 ×10^15 cm-3 in the active region is believed to have the best overall performances.
2μm InGaSb/AlGaAsSb strained quantum wells and a tellurium-doped GaSb buffer layer were grown by molecular beam epitaxy（MBE）.The growth parameters of strained quantum wells were optimized by AFM, XRD and PL at 77 K.The optimal growth temperature of quantum wells is 440℃.The PL peak wavelength of quantum wells at 300 K is 1.98μm,and the FWHM is 115 nm.Tellurium-doped GaSb buffer layers were optimized by Hall measurement.The optimal doping concentration is 1.127×10^（18） cm^（-3） and the resistivity is 5.295×10^（-3）Ω·cm.
A high power GaSb-based laser diode with lasing wavelength at 2 μm was fabricated and optimized. With the optimized epitaxial laser structure, the internal loss and the threshold current density decreased and the internal quantum efficiency increased. For uncoated broad-area lasers, the threshold current density was as low as 144 A/cm2 （72 A/cm^2 per quantum well）, and the slope efficiency was 0.2 W/A. The internal loss was 11 cm^-1 and the internal quantum efficiency was 27.1%. The maximum output power of 357 mW under continuous-wave operation at room temperature was achieved. The electrical and optical properties of the laser diode were improved.
