As an essential structure of infrared semiconductor lasers, the optical properties of InGaAsSb/AlGaAsSb multiple quantum wells need to be fully investigated. In this paper, the temperature and excitation power-dependent photoluminescence (PL) spectra of the InGaAsSb/AlGaAsSb MQWs are measured. A strong free exciton emission with a photon energy of 0.631 eV was observed at room temperature. Besides the main peak, an obvious shoulder peak, located at the low photon energy position under low temperature range (T≤90 K), was confirmed to be an emission of defect related localized carriers by power-dependent PL spectra. The power-dependent PL spectra were dominated by the localized carriers emission under low excitation power (Iex≤20 mW), while the free-exciton emission dominated the PL spectra gradually when excitation power higher than 40 mW. This phenomenon is ascribed to the dissociation of localized states. Our work is of great significance for the device applications of InGaAsSb/AlGaAsSb multiple quantum wells.

中文翻译：

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分子束外延生长的四元 InGaAsSb/AlGaAsSb 多量子阱中局域态发射的研究

作为红外半导体激光器的基本结构，InGaAsSb/AlGaAsSb多量子阱的光学特性需要充分研究。在本文中，测量了 InGaAsSb/AlGaAsSb MQW 的温度和激发功率相关光致发光 (PL) 光谱。在室温下观察到具有 0.631 eV 光子能量的强自由激子发射。除了主峰外，一个明显的肩峰位于低温范围（T≤90 K）下的低光子能量位置，通过功率相关的PL光谱证实是缺陷相关局部载流子的发射。功率相关的PL光谱在低激发功率（Iex≤20 mW）下以局域载流子发射为主，而当激发功率高于40 mW时，自由激子发射逐渐主导PL光谱。这种现象归因于局部状态的解离。我们的工作对InGaAsSb/AlGaAsSb多量子阱的器件应用具有重要意义。