Development of InGaAs/GaAs strained single quantum well laser by phase looked epitaxy method.

采用光致发光（PL）方法研究了InGaAs/GaAs应变单量子阱（SSQW）结构的结晶度和光学性质与晶体生长条件的关系。用MBE法制备的InGaAs/GaAs SSQW结构在540℃时的PL光谱显示，QW发光线的峰值向较低的波长移动，而不是理论估计的位置。这说明In原子在InGaAs层的MBE生长过程中蒸发，导致In_<chi>Ga_<1-chi>As活性层中的chi减少。由于In蒸发是热增强过程，因此认为降低沉积温度可以有效抑制In蒸发。为了降低InGaAs层的生长温度，我们采用MEE法生长InGaAs层。被认为是降低AlGaAs/GaAs合金半导体体系生长温度的有效技术。MEE法生长的SSQW结构的PL谱图表明，将生长温度降低到290ºC可以控制In的蒸发。然而，在540℃时，PL线的FWHM比MBE制成的SSQW结构的FWHM宽。RHEED图谱也表明，低温下制备的薄膜的晶体质量不如高温生长的薄膜。过量的As粘附和III族原子的低迁移率被认为是决定低温生长SSQW结构晶体质量的关键因素。因此，我们通过增加III族原子的迁移时间和降低As分压来优化MEE的低温生长条件。经优化的低温MEE工艺制备的SSQW结构在光学和晶体学性能上与高温MBE工艺制备的薄膜相当。实验结果表明，通过优化的低温MEE工艺，可以制备出高度可控的InGaAs/GaAs SSQW结构的组成、结晶度和光学质量，这可能是制备SSQW激光器件的有前途的工艺。少

The crystallinity and optical property of InGaAs/GaAs strained single quantum well(SSQW) structure were studied by photoluminescence (PL) method in relation to the crystal growth conditions. A PL spectrum of InGaAs/GaAs SSQW structure made by MBE at 540ﾟC showed a peak shift of the QW luminescence line toward the lower wave length than the theoretically estimated position. This fact suggests that In atoms evaporate during MBE growth of InGaAs layer, resulting in the decrease of chi in In_<chi>Ga_<1-chi>As active layer. Because the In evaporation is thermally enhanced process, it is considered that lowering the deposition temperature is effective to suppress the In evaporation.In order to reduce the growth temperature of the InGaAs layer, we grow the InGaAs layer by applying MEE method, which.is known as a effective technique to reduce the growth temperature of AlGaAs/GaAs alloy semiconductor system. The PL spectra of the SSQW structure grown by MEE method showed that the In evaporation … More could be controlled by decreasing the growth temperature to 290ﾟC. However, FWHM of the PL line became broader than the one from the SSQW structure made by MBE at 540ﾟC. Also the RHEED pattern showed that the crystal quality of the film made at low temperature is inferior to the high temperature grown film.The excess As adhesion and the low mobility of the group III atoms were believed to be the key factors to determine the crystal quality of the SSQW structure grown at low temperatures. So we optimized the low temperature MEE growth condition by increasing the migration time of the group III atoms and by reducing the As partial pressure. The SSQW structure made by the optimized low temperature MEE process showed the comparable qualities in optical and crystallographic properties to the films made by the high temperature MBE process.It is demonstrated that the highly controlled InGaAs/GaAs SSQW structure in composition, crystallinity and optical quality were made by the optimized low temperature MEE process, which may be the promising process to obtain the SSQW laser devices. Less