基于液滴外延技术变Al、Ga组分对GaAs表面液滴生长形貌的影响

液滴外延技术不仅适用于晶格失配,也适用于晶格匹配材料系统,且易于制备低维半导体结构,如低密度量子点、环等.本文研究了液滴外延法在GaAs表面进行不同Al、Ga组分的量子点生长.在实验中用反射式高能电子衍射仪(Reflection High Energy Electron Diffraction, RHEED)对样品进行原位监控.通过控制Al、Ga液滴的沉积速率来控制液滴同时沉积在衬底上形成的组分.研究发现,随着Al组分的增加,量子点逐渐变得密集,润湿角变低.在Al组分增高超过0.5之后,出现了大小不一的量子点,且量子点密度出现指数型增长.对此进行研究分析,给出了一个经验公式,并就现象进行了解释.

Effects of Al and Ga composition on the growth morphology of GaAs droplets based on droplet epitaxial technology

Droplet epitaxy technology is not only suitable for lattice mismatch, but also suitable for lattice matched material systems, and is easy to prepare low-dimensional semiconductor structures, such as low-density quantum dots, rings, etc. In this paper, the growth of quantum dots with different Al and Ga compositions on GaAs surface by droplet epitaxy method was studied. In the experiment, the samples were monitored in situ with Reflection High Energy Electron Diffraction (RHEED). The composition of Al and Ga droplets deposited on the substrate was controlled by controlling the deposition rate of Al and Ga droplets. It was found that the quantum dots become denser and the wetting angle became lower with the increase of Al composition. When the Al component increased by more than 0.5, quantum dots of different sizes appeared, and the dot density increased exponentially. An empirical formula is given and the phenomenon is explained.