淀积在不同小倾角蓝宝石衬底的n型GaN的研究

采用金属有机物化学淀积技术在不同倾角（0°—03°）的蓝宝石衬底上外延n型GaN.通过原子力显微镜观察到n型GaN均呈台阶流生长模式，02°和03°倾角衬底的n型GaN表面台阶朝向相同、分布均匀，明显地看到在0°倾角衬底的n型GaN表面由台阶重构直接导致的台阶朝向随机分布、疏密不匀的形貌.电子背散射分析表明，在0°倾角衬底的n型GaN外延层的应力随外延厚度增加而增加，而02°和03°倾角衬底的n型GaN外延层的应力没有明显的变化.电学和光学特性研究表明，02°和03°倾角衬底的n型GaN有较高的电子浓度和较低的黄光带与近带边强度之比. 关键词： 金属有机物化学淀积 氮化物 原子力显微镜 光致发光

Investigation of n-type GaN deposited on sapphire substrate with different small misorientations

The n type GaN films have been grown on c plane sapphire with different small misorientation（0°—03°）by metal organic chemical vapor deposition. It was observed by atomic force microscopy that the n type GaN has the step flow growth mode, the flow steps of the n type GaN surface are uniformly distribution on 02° and 03° misorientation sapphire substrate, it was observed clearly that random and poor distribution of the flow steps was caused by the step reconstruction on 0° misorientation sapphire substrate. The image quality parameter of electron back scatter diffraction indicated that the strains increase as the n type GaN epilayer thickness increases on 0° misorientation sapphire substrate but do not vary obviously on 02° and 03° misorientation sapphire substrates. Electrical and optical properties demonstrated the n type GaN grown on the 02° and 03° misorientation sapphire substrates have higher electron concentration and lower ratio of the intensity of yellow band to near band edge.