人工晶体学报, 2020, 49 (12): 2268, 网络出版: 2021-01-26
In原子在GaAs(001)表面的成核与扩散研究
Nucleation and Diffusion of In Atom on GaAs(001) Surface
InAs量子点 In沉积量 液滴外延 临界厚度 成核机理 光电特性 InAs quantum dot deposition amount of indium droplets epitaxy critical thickness nucleation mechanism photoelectric property
摘要
近年来,半导体量子点特别是InAs量子点的基本物理性质和潜在应用得到了广泛研究。许多研究者利用InAs量子点结构的改变以调制其光电特性。本文采用液滴外延法在GaAs(001)表面沉积了不同沉积量的In(3 ML、4 ML、5 ML),以研究In的成核机制和表面扩散。实验发现,随着In沉积量的增加,液滴尺寸(包括直径、高度)明显增大。不仅如此,在相同的衬底温度下,沉积量越大,液滴密度越大。利用经典成核理论,计算了GaAs(001)表面In液滴形成的临界厚度为0.57 ML,计算的结果与已报道的实验一致。从In原子在表面的迁移和扩散,以及衬底中Ga和液滴中的In之间的原子互混原理解释了In液滴形成和形貌演化的机理。实验中得到的In液滴临界厚度以及In液滴在GaAs(001)上成核机理,可以为制备InAs量子点提供实验指导。
Abstract
In recent years, the basic physical properties and potential applications of semiconductor quantum dots, especially InAs quantum dots, have been extensively studied. Many researchers use the structural changes of InAs quantum dots to modulate their photoelectric properties. Various amount of indium (3 ML, 4 ML, 5 ML) were deposited on GaAs(001) surface by droplets epitaxy for investigating the nucleation mechanisms and surface diffusion of indium. As the amount of indium deposition increases, the droplet size (including diameter and height) increases obviously. Not only that, higher deposition amount also leads to higher density of droplets at the same substrate temperature. The critical thickness of indium droplet formation was theoretically calculated as 0.57 ML on the GaAs (001) surface. It is in agreement with experimental result. The mechanism of the formation and morphology evolution of droplets is explained by diffusion and intermixing between the gallium and indium migration. The critical thickness of In droplet obtained in the experiment and the nucleation mechanism of In droplet on GaAs(001) can provide experimental guidance for InAs quantum dots growth.
王一, 丁召, 魏节敏, 杨晨, 罗子江, 王继红, 郭祥. In原子在GaAs(001)表面的成核与扩散研究[J]. 人工晶体学报, 2020, 49(12): 2268. WANG Yi, DING Zhao, WEI Jiemin, YANG Chen, LUO Zijiang, WANG Jihong, GUO Xiang. Nucleation and Diffusion of In Atom on GaAs(001) Surface[J]. Journal of Synthetic Crystals, 2020, 49(12): 2268.