Abstract Van der Waals epitaxy (vdWE) of three-dimensional (3D) semiconductors on 2D materials has broad prospects for integrating their distinguishing features. However, many defects, including grain boundaries, basal plane stacking faults (BSFs), and threading dislocations (TDs), exist in the 3D semiconductors, and the origin of those defects has not been studied systemically. Here, we investigate the origin of microstructural defects systemically in a case of single-crystalline GaN films vdWE on graphene. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used for macroscopic and microscopic characterization of the defects of GaN films. Low-angle grain boundaries were existed in the initial 1–2 μm, and the BSFs were formed at the interface of GaN about 200 nm. Moreover, the mixed TDs, as one of threading TDs, were the main line defects in GaN films. This research provides a systematic introduction of various defects (volume, plane, and line defects) in 3D semiconductors vdWE on 2D materials.

中文翻译：

---

石墨烯上范德华外延单晶薄膜微观结构缺陷的起源

摘要 二维材料上三维 (3D) 半导体的范德华外延 (vdWE) 具有整合其显着特征的广阔前景。然而，3D半导体中存在许多缺陷，包括晶界、基面堆垛层错（BSFs）和螺纹位错（TDs），这些缺陷的起源尚未得到系统研究。在这里，我们在石墨烯上的单晶 GaN 薄膜 vdWE 的情况下系统地研究了微观结构缺陷的起源。使用电子背散射衍射 (EBSD) 和透射电子显微镜 (TEM) 对 GaN 薄膜的缺陷进行宏观和微观表征。初始 1~2 μm 处存在小角度晶界，在 GaN 界面约 200 nm 处形成 BSF。此外，混合 TD 作为线程 TD 之一，是 GaN 薄膜中的主要线缺陷。本研究系统地介绍了 2D 材料上 3D 半导体 vdWE 中的各种缺陷（体积、平面和线缺陷）。