砷化镓表面摩擦化学去除的机理及应用研究

Due to its excellent photoelectric property, gallium arsenide (GaAs) based quantum dots (QDs) have potential applications in new energy technologies, photoelectric detection, and so on. However, disorder growth of QDs becomes the great obstacle for further improving their performances. The key procedure for the site-controlled formation of QDs is to fabricate nanoscale holes with low defect to induce the nucleation of QDs. Lots of lattice defects were observed on the holes on GaAs realized by some traditional methods, such as nanoindentation and etching by high energy beam, which is unqualified for QDs generation. Material removal by tribochemical wear is a feasible approach to form the nucleation site with low defect lattice on GaAs. The proposed project is hereby focused on investigating the behaviors, mechanism and controlling of tribochemical removal of GaAs systematically. Firstly, the effect of various experimental conditions on the tribochemistry wear will be investigated respectively. Based on the analysis of coupling results of mechanical interaction and chemical reaction, the mechanism to understand the tribochemical removal of GaAs will be revealed. Finally, the controllable material removal of GaAs will be completed by optimizing the experimental parameters. The proposed project research is expected to enrich the art of the current state of fundamental theory in nanotribology, and to realize the site-controled growth of high quality QDS on GaAs, promoting their applications in new high-tech field, such as new energy.

砷化镓表面所形成的量子点具有优异的光电特性，在新能源和光电探测等高新科技领域展示出强劲的应用前景。然而，量子点生长的无序性成为限制其性能提升的巨大障碍。定位构筑量子点的关键是加工出诱导量子点生长的低缺陷纳米级凹坑。目前，常规的纳米压痕和高能束刻蚀等方法易导致砷化镓衬底形成大量缺陷，难以满足量子点的生长要求。而摩擦化学方法可在低载下实现局部区域材料的去除，是在砷化镓衬底表面形成低缺陷纳米凹坑的有效途径。为此，本项目拟系统开展砷化镓摩擦化学去除的行为、机理及应用研究。在阐明各种因素对砷化镓摩擦化学去除的影响规律的基础上，深入探究材料去除过程中机械和化学的耦合作用，以揭示砷化镓的摩擦化学去除机制；最后，通过对实验工况的优化，实现砷化镓表面材料的低损伤可控去除。该研究不仅有助于丰富纳米摩擦学基础理论，而且有望实现砷化镓表面高质量量子点的定位生长，从而有力推动其在新能源等领域的实用化进程。

砷化镓（GaAs）表面所形成的量子点具有优异的光电特性，在新能源和光电探测等高新科技领域展示出强劲的应用前景。然而，量子点生长的无序性成为限制其性能提升的巨大障碍。定位构筑量子点的关键是加工出诱导量子点生长的低缺陷纳米级凹坑。常规的纳米压痕和高能束刻蚀等方法易导致砷化镓衬底形成大量缺陷，难以满足量子点的生长要求。而摩擦化学方法可在低载下实现局部区域材料的去除，可望成为在GaAs衬底表面构筑低缺陷纳米凹坑的有效途径。为此，本项目系统的开展了GaAs摩擦化学去除的行为、机理及应用研究。所开展的主要研究内容及取得的重要结果如下：.(1) 考察了实验条件（法向载荷、刻划次数、速度等）和环境气氛（不同湿度、液下、氮气环境等）对GaAs表面的摩擦化学去除的影响，其除深度随着速度（0.1 μm/s-1000 μm/s）的增加而降低，随着湿度（1%-90%）的增加而增加，液下去除深度最大；.(2) 利用高分辨透射电镜、微区X-射线光电子能谱、微区拉曼等分析手段，考察了GaAs表面微观去除区域/断面的化学成分和微观结构，在摩擦化学去除后的断面上未见明显的晶格损伤；在此基础上，揭示了GaAs表面的摩擦化学去除是通过针尖-GaAs界面粘着并成键、界面键在GaAs端断裂、表面氧化物的溶解及移出这一系列过程实现的；.(3) 开展了GaAs表面的摩擦诱导纳米加工（含摩擦诱导选择性刻蚀）的原理研究，并考察了刻蚀时间和刻蚀温度对GaAs表面的摩擦诱导选择性刻蚀的影响，发展了GaAs表面的无损加工方法。.总之，本研究通过对GaAs表面摩擦化学去除行为和机理的研究及对GaAs表面摩擦选择性刻蚀的研究，提出了GaAs表面的量子点定位生长成核位置的加工方法。本研究不仅有助于丰富纳米摩擦学基础理论，而且有望实现砷化镓表面高质量量子点的定位生长，从而有力推动其在新能源等领域的实用化进程。