MOCVD生长InGaN合金的表面形貌与光学性质研究

基于X射线衍射和原子力显微分析，研究了MOCVD生长的InGaN合金的表面形貌和光致发光光谱。结果发现本实验所用InGaN合金样品表面形貌呈现类花生状微结构团簇，纳米尺度较小的球状富铟InGaN颗粒附着在较大颗粒上；X射线衍射数据计算得微晶粒度折合当量直径约23nm。原子力显微测量得典型的微结构团簇横向宽度约400nm-900nm，表面粗糙度在所选择的6．430μm区域内方均根值为11．52nm，3．58μm区域内方均根值为8．48nm。在室温下用325nm连续激光激发测得样品的表面发光光谱，结果显示光致发光光谱出现多峰结构，其主要发光峰峰值波长分别位于569nm、532nm和497nm。理论计算分析认为发光光谱多峰结构可能是由于InGaN／GaN异质结构形成的F-P垂直腔中多光束干涉调制效应造成的，同时InGaN合金的尺度和组分涨落导致较宽的发光峰。研究结果对设计GaN基半导体光电子器件具有一定的参考价值。

Investigation on morphological and optical properties of InGaN alloy grown by metalorganic chemical vapor deposition

The microstructure and photoluminescence spectra of the InGaN/GaN epilayers grown by MOCVD were investigated based on XRD and AFM analyses. It was found that the ternary alloy tend to form peanut-like microstructure on which much smaller In rich InGaN grain was attached. Observation of the multi-peak structure of the photoluminescence spectra gives clear proof of the Fabry-Pe' rot interference effect in the InGaN/GaN vertical cavity. These findings are merit to design the novel optoelectronic devices based on Ⅲ-nitride wide-band-gap semiconductors.