In_(0.5)Ga_(0.5)As/In_(0.5)Al_(0.5)As应变耦合量子点的形貌和光学性质

Morphologic and optical properties of In_(0.5)Ga_(0.5)As/In_(0.5)Al_(0.5)As strain-coupled quantum dots

提出了利用分子束外延方法生长In0.5Ga0.5As/In0.5Al0.5As应变耦合量子点,并分析量子点的形貌和光学性质随GaAs隔离层厚度变化的特点。实验结果表明,随着耦合量子点中的GaAs隔离层厚度从2 nm增加到10 nm,In0.5Ga0.5As量子点的密度增大、均匀性提高,Al原子扩散和浸润层对量子点PL谱的影响被消除,而且InAlAs材料的宽禁带特征使其成为InGaAs量子点红外探测器中的暗电流阻挡层。由此可见,选择合适的GaAs隔离层厚度形成InGaAs/InAlAs应变耦合量子点将有益于InGaAs量子点红外探测器的研究。

In0.5Ga0.5As/In0.5Al0.5As strain-coupled quantum dots （QDs） grown by molecular beam epitaxy method is reported and the dependences of their morphological and optical properties on the GaAs separation layer are investigated. With increasing the thickness of GaAs separation layer from 2 nm to 10 nm, the areal density of In0.5Ga0.5As QDs is increased, their uniformity is also improved. The influences of aluminum atom diffusion and wetting layer on the photoluminescence spectrum are eliminated. Additionally, the wider band gap of InAlAs enables it to act as blocking layer of the dark current in InGaAs quantum dot infrared photodetectors （QDIPs）.The InGaAs/InAlAs strain-coupled quantum dots are useful to the research of InGaAs QDIPs.