【作者】 李弋； 谢自力； 刘斌； 傅德颐； 张荣； 郑有炓；

【Author】 Li Yi,Xie Zili,Liu Bin,Fu Deyi,Zhang Rong,Zheng Youliao (Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, Department of Physics,Nanjing University,Nanjing 210093,China)

【机构】 南京大学物理系江苏省光电功能材料重点实验室；

【摘要】 使用MOCVD直接外延r面蓝宝石衬底得到非极性a面GaN薄膜。高分辨X射线衍射发现薄膜晶体结构的面内各向异性,利用倒易空间法获得[0001]和[100]方向横向关联长度分别为41.9、14.8 nm,解释了面内各向异性的一个原因,在这两个方向N原子的悬挂键数目的差异导致了Ga原子这两个方向上的扩散长度不同,是面内各向异性的另一个重要原因。AFM结果显示a面GaN薄膜表面较平整,表面粗糙度均方根仅为3.9 nm,表面沿[0001]方向起伏的条纹再次验证了a面GaN的面内各向异性。更多还原

【Abstract】 The non-polar a-plane GaN thin films on r-plane sapphire substrate were grown directly without a buffer layer by MOCVD.The HR XRD characterized crystal structural resulted the films were in-plane anisotropic.The lateral correlation along the[0001]and[100]direction were 41.9 nm and 14.8 nm respectively by using RSMs,and it was one reason for in-plane anisotropy. The difference in the number of nitrogen dangling bonds at the step edge for the two-crystal directions causing a difference in migration length of gallium adatoms was another reason for in-plane anisotropy.The AFM results show that GaN thin films are smooth surface with a RMS roughness of 3.9 nm.Wavy stripe along the[0001]direction can be observed to indicate the a-plane GaN in-plane anisotropy again.更多还原