发光学报2006，Vol.27Issue(4)：514-518,5.
用X射线衍射法测定氮化镓马赛克结构中的面内扭转角
Twist Angle of Mosaic Structure in GaN Films Determined by X-ray Diffraction
摘要
Abstract
GaN and its related Ⅲ - Ⅴ alloys have received much attention in recent years for their potential ability in short-wavelength light emitting diodes, laser diodes and photodetectors. However, due to the lack of a suitable latticematched bulk substrate, they are usually grown on Al2O3 or SiC substrates with a high density of threading dislocations (TDs). The origin of these dislocations has been suggested to be due to a peculiar growth mode-mosaic structure which can be characterized by means of tilt and twist angles. For wurtzite GaN the mean tilt angle of mosaic structure is related to the FWHM of (0002) diffraction peak,which can be easily measured by using XRD. Unfortunately, the twist of lattice planes is difficult to be measured directly. High-resolution X-ray diffraction was used to determine the twist angle of mosaic structure in GaN epitaxial layers grown on sapphire by metal-organic chemical vapor deposition (MOCVD). Rocking curves of five planes were investigated, (0002); (10(-1)3); (10(-1)2); (10(-1)1 ); and (20(-2)1) respectively. Pseudo-Voigt function was used to simulate the rocking-curve of every plane. The twist angles of GaN layers were easily obtained by extrapolating the full width at half maximum (FWHM) of diffraction peak of the planes. The twist angles of the films measured directly by φ-scans of the (1(-1)00) reflection in grazing-incidence X-ray diffraction (GIXRD) agree well with the extrapolated results. As far as we know, it's the first time that the extrapolated method was checked to be valid in this material, and the results are useful for the further study of GaN films.关键词
氮化镓/马赛克结构/扭曲角/掠入射X射线衍射/X射线衍射Key words
GaN/mosaic structure/twist angle/GIXRD/X-ray diffraction分类
数理科学引用本文复制引用
苏月永,陈志涛,徐科,郭立平,潘尧波,杨学林,杨志坚,张国义..用X射线衍射法测定氮化镓马赛克结构中的面内扭转角[J].发光学报,2006,27(4):514-518,5.基金项目
国家自然科学基金资助项目(60376005,60577030) Project supported by National Natural Science Foundation of China (60376005, 60577030) （60376005,60577030）
