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采用自制的立式HVPE设备,在GaN/蓝宝石复合衬底上生长了GaN厚外延膜,利用AFM,SEM,XRD,RBS/Channeling,CL,PL以及XPS等技术分析了厚膜的结构和光学性能.结果表明,外延层表面具有台阶结构,接近以层流生长方式二维生长,一些六角形的坑出现在膜表面,坑区具有很强的发光.腐蚀试验显示EPD仅8×106cm-2;XRD和RBS/channeling表明GaN膜具有较好的晶体质量;PL结果也证明外延层具有高的质量,出现了尖锐的带边峰,半高宽仅67meV,同时出现了黄带和红外带,这些带的出现可能是由本征缺陷和C,O等杂质引起的.
GaN epitaxial films were grown on GaN / sapphire composite substrates by using self-made vertical HVPE devices. The structure and optical properties of the films were analyzed by AFM, SEM, XRD, RBS / Channeling, CL, PL and XPS techniques The results show that the surface of the epitaxial layer has a stepped structure, which grows two-dimensionally close to laminar flow growth, some hexagonal pits appear on the surface of the film and the pits have a strong luminescence.The corrosion test shows that the EPD is only 8 × 106cm-2; XRD and RBS / channeling show that the GaN film has good crystal quality. The PL result also proves that the epitaxial layer has a high quality with a sharp band edge with a full width at half maximum of 67meV and yellow and infrared bands The appearance of the band may be caused by intrinsic defects and C, O and other impurities.