温度对GaSb/GaAs量子点尺寸分布的影响

采用低压金属有机物化学气相沉积 (LP-MOCVD) 法制备GaSb/GaAs量子点。通过对不同生长温度的样品进行分析发现温度的变化对GaSb/GaAs量子点的相位角无明显影响,量子点的形状是透镜型。由于量子点特殊的应力分布,可实现量子点的"自限制"生长。量子点的化学势不连续性以及Ostwald熟化机制的影响使得量子点尺寸分布在一定范围内不连续,会出现两种尺寸模式的量子点生长。Sb原子的表面迁移率对GaSb/GaAs量子点生长有较大的影响。升高温度可有效改善量子点的分立性,在升温过程中量子点体现出其熟化过程,高温时表面原子的解析附作用对量子点尺寸和密度的影响较大。

Effect of Growth Temperature on Size Distribution of GaSb/GaAs Quantum Dots

The GaSb/GaAs quantum dots (QDs) were prepared by the technique of low pressure metalorganic chemical vapor deposition (LP-MOCVD). Based on analysis of samples for different growth temperatures, it turns out that the growth temperatures have little contribution to the morphology of GaSb/GaAs QDs and the shape of GaSb/GaAs QDs turns to be lens. The stress distributions between GaSb/GaAs interface lead to the "self-limiting" formation of GaSb QDs. Besides, due to discontinuous chemical potential of QDs, coupled with the effect of curing mechanism of Ostwald, the size distribution of QDs in certain range is discrete and two modes of QDs size appear. The surface mobility of antimony (Sb) adatoms has an important influence on the growth of GaSb/GaAs QDs. The discreteness of QDs can be efficiently improved by raising the growth temperature. With the process of heating up, the curing process of QDs can be presented.