Fabrication of high-ordered hole arrays by anodization of GaAs substrates and their optical poperties

我们提出了一种利用分子束外延(MBE)技术在(001)氧化的GaAs衬底上控制InAs点位置的新方法。在氨水溶液中，在GaAs阳极氧化形成的空洞底部选择性地生长了InAs点。然而，空洞的尺寸变化对InAs点的尺寸有很大的影响。在本研究中，我们研究了GaAs阳极氧化形成的空洞的规律性对InAs点分子束外延生长的影响。阳极氧化后，扫描电子显微镜图像显示在表面形成了空洞。在最佳阳极氧化条件下，孔洞的平均直径约为200 nm，标准偏差约为20 nm。在阳极氧化前采用电子束曝光和干法刻蚀技术在衬底上形成三角形图形的情况下，进一步改善了尺寸变化。在空穴平均直径约为80 nm的情况下，在蜂窝空穴的每个底部选择生长一个InAs点，InAs点的平均直径约为40 nm。光致发光光谱表明，量子点在约1.2μm处有一个宽峰。

We have proposed a novel method for controlling the site of InAs dots using molecular-beam epitaxial(MBE) growth on anodized (001) GaAs substrates. InAs dots were selectively grown at the bottom of hollows formed by anodization of GaAs in an NH_4OH solution. However, the size variation of hollows strongly affected the size of InAs dots. In this study, we investigated on the effects of regularity of hollows which are formed by anodization of GaAs substrates on the MBE growth of InAs dots.After the anodizaiotn, scanning electron microscope images show that hollows were formed on the surface. In the case of the optimal anodization, the average diameter and the standard deviation of hollows were about 200 and 20 nm, respectively. In the case of a triangular pattern was formed on the substrate using electron beam lithography and dry etching technique before the anodization, the size variation was further improved.InAs dots were grown by MBE on honeycomb hollows formed by anodizatpn of GaAs substrates. In the case of the average diameter of hollows was about 80 nm, one InAs dot was selectively grown at each bottom of honeycomb hollows, and the average diameter of InAs dots was about 40 nm. Photolmninescence spectrum shows that a broad peak from quantum dots was observed at about 1.2 μm.