中文摘要：

利用高分辨X射线衍射仪（XRD）分析了长时间退火前后的GaN样品，通过对各个样品的（0002）面摇摆曲线进行线形拟合及分析，发现虽然退火后摇摆曲线的半峰宽变大，但面外倾斜角（tilt）的值却变小，从而螺型穿透位错（TD）密度变小，这与化学腐蚀实验的结果一致．我们的结果表明，线形拟合在利用XRD研究GaN薄膜材料结构的过程中是十分必要的，而不能用摇摆曲线的展宽直接表征TD密度。

英文摘要：

High-resolution X-ray diffraction is utilized to analyze the micro-structure of annealed and as-grown GaN thin films grown by metalorganic chemical vapor deposition. Profile-fitting analyses indicate that the annealed ones have larger full widths at half maximum of （0002） rocking curve and lower densities of screw-type threading dislocations than the asgrown samples. A chemical etching experiment supports the above results. Our results indicate that profile-fitting is necessary when XRD is used to characterize the structure of GaN thin films.