摘要
本文首次报道了在腐蚀图形的（３１１）Ａ衬底上，一种新型三角形点结构的ＭＢＥ生长及其量子阱限制能量的横向变化研究．原子力显微镜三维图象清晰地显示出在原腐蚀凹面图形之间的平面区域，ＭＢＥ选择性生长形成了均匀的三角形收缩结构，其尖角沿［２３３］方向，收缩面由对称的｛１１１｝Ａ面构成．低温阴极荧光谱和图象测试研究结果表明：这种点状外延结构存在三个分离的荧光发射区域，分别对应于三个不同的激发光波长．说明这种点结构中量子阱层厚度的变化引入了量子阱限制能量的横向变化．低温微区光致发光谱测试得到高度可分辨的三个发光峰，结果说明在围绕点状结构顶部区域形成了１３ｍｅＶ横向势垒，且具有较高的辐射复合发光效率．
Abstract Highly ordered triangular shaped dot like (TD) structure has been obtained by Molecular Beam Epitaxy (MBE) on square hole patterned (311)A substrate for the first time. Three dimensional atomic force microscopy (AFM) photography presents that the TD structure is developed between the original holes of the pattern and formed with tip like structures, which are constructed of smooth {111}A facets and pointing 3] orientation. The low temperature Cathodeluminescence emissions excited at three different wavelengths corresponding to three identified regions of the TD structure reveal that the lateral band gaps are induced by the QW thickness variations around the top portion of the TD structure. The spectra of micro photoluminescence further indicate that the three highly resolved peaks are originated from the three portions of the TD structure showing lateral barrier of 13meV between the top portion and the nearby smooth regions with efficient radiative recombination.
