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采用脉冲激光双光束沉积系统在Si(111)衬底上生长了掺Mg的GaN薄膜和未掺杂GaN薄膜。利用X射线衍射 (XRD)、原子力显微镜 (AFM)、室温范德堡霍尔测量及光致发光 (PL)光谱对两类薄膜进行对比分析 ,结果显示 ,所生长的GaN薄膜均为六方纤锌矿晶体结构 ,掺Mg可细化所生长的GaN薄膜晶粒。随着掺Mg量的增加 ,GaN薄膜无需后处理即可由n型导电转化为 p 型导电 ,GaN薄膜的光学性能随 p型载流子浓度增大而提高 ;然而掺Mg却导致GaN薄膜结晶质量下降 ,掺镁量过大的GaN薄膜中 p 型载流子浓度反而减少 ,光致发光中黄发射峰增强较大。研究表明通过优化脉冲激光双光束沉积参数无需任何后处理可直接获得高空穴载流子浓度的 p 型GaN薄膜
A Mg-doped GaN film and an undoped GaN film were grown on a Si (111) substrate by a pulsed laser dual-beam deposition system. The comparative analysis of the two types of films by X-ray diffraction (XRD), atomic force microscopy (AFM), room temperature Vanderbilt Hall measurement and photoluminescence (PL) spectroscopy showed that the grown GaN films were all hexagonal Mineral crystal structure, doped with Mg can refine the growth of GaN thin film grain. With the increase of Mg doping amount, the GaN film can be transformed into n-type conductivity without p reprocessing. The optical properties of GaN film increase with the increase of p-type carrier concentration. However, Mg doping results in the crystalline quality of GaN film The p-type carrier concentration in the GaN film with excessive Mg content decreases but the yellow emission peak in photoluminescence increases greatly. The research shows that the p-type GaN film with high hole carrier concentration can be directly obtained without any post-processing by optimizing the pulsed laser dual-beam deposition parameters