采用光荧光和阴极荧光方法 ,对 Ga N外延层中的黄色和蓝色发光进行测量分析 ;同时 ,采用原子力显微镜、扫描电镜及其能谱测量外延层中的缺陷。结果表明 ,黄色和蓝色发光与残留杂质有关。采用第一原理计算结果显示 ,残留 C、O杂质、本征缺陷等是黄色和蓝色的可能物理起源。采用原子力显微镜、扫描电镜、透射电镜及其能谱对 Ga N/Al Ga N异质结中的纳米管进行观测 ,了解了纳米管的形貌。结果表明 ,构成纳米管的小面可能是外延过程中表面吸附引起的 ;计算结果显示 ,纳米管形貌变化与 Ga N/Al Ga N界面处晶格失配应力有关。采用透射电镜观察外延层中沉积物及其周围位错的结构表明 ,沉积物附近应力的存在是位错产生的主要原因 The yellow and blue luminescence in the Ga N epitaxial layer were measured and measured by the method of fluorescence and cathodoluminescence. At the same time, the defects in the epitaxial layer were measured by atomic force microscopy, scanning electron microscopy and their energy spectra. The results show that the yellow and blue luminescence and residual impurities. Calculations using the first principle show that residual C, O impurities, intrinsic defects, etc. are possible yellow and blue physical origins. Atomic force microscopy, scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy were used to observe the nanotubes in Ga N / Al Ga N heterojunctions. The results show that the surface of the nanotubes may be caused by the surface adsorption during the epitaxial process. The calculated results show that the nanotube morphology is related to the lattice mismatch stress at the Ga N / Al Ga N interface. The observation of the structure of the sediments and the surrounding dislocations in the epitaxial layer by TEM shows that the existence of stress near the sediments is the main reason for the dislocation