College of Electronics and Information, Kwangwoon University, Nowon-gu Seoul 139-701, South Korea.
Nanoscale Res Lett. 2012 Oct 3;7(1):550. doi: 10.1186/1556-276X-7-550.
In this paper, the formation of Ga droplets on photo-lithographically patterned GaAs (100) and the control of the size and density of Ga droplets by droplet epitaxy using molecular beam epitaxy are demonstrated. In extension of our previous result from the journal Physical Status Solidi A, volume 209 in 2012, the sharp contrast of the size and density of Ga droplets is clearly observed by high-resolution scanning electron microscope, atomic force microscope, and energy dispersive X-ray spectrometry. Also, additional monolayer (ML) coverage is added to strength the result. The density of droplets is an order of magnitude higher on the trench area (etched area), while the size of droplets is much larger on the strip top area (un-etched area). A systematic variation of ML coverage results in an establishment of the control of size and density of Ga droplets. The cross-sectional line profile analysis and root mean square roughness analysis show that the trench area (etched area) is approximately six times rougher. The atomic surface roughness is suggested to be the main cause of the sharp contrast of the size and density of Ga droplets and is discussed in terms of surface diffusion.
本文通过分子束外延的液滴外延，展示了在光刻图形化 GaAs（100）上 Ga 液滴的形成，以及对 Ga 液滴尺寸和密度的控制。在我们 2012 年发表于《物理状态 solidi A》第 209 卷的先前研究结果的基础上，通过高分辨率扫描电子显微镜、原子力显微镜和能量色散 X 射线光谱仪，清晰地观察到 Ga 液滴尺寸和密度的鲜明对比。此外，还增加了单层（ML）覆盖以增强结果。在沟槽区域（刻蚀区域），液滴的密度是数量级更高，而在条带顶部区域（未刻蚀区域），液滴的尺寸大得多。对 ML 覆盖度的系统变化导致 Ga 液滴尺寸和密度的控制得以建立。横截面线轮廓分析和均方根粗糙度分析表明，沟槽区域（刻蚀区域）的粗糙度约为六倍。原子表面粗糙度被认为是 Ga 液滴尺寸和密度鲜明对比的主要原因，并从表面扩散的角度进行了讨论。
