The van der Waals epitaxy (vdWE) of three-dimensional (3D) semiconductors on 2D materials has broad prospects for integrating the unique advantages of both. In this study, multilayer graphene (MLG) was synthesized by plasma enhanced chemical vapor deposition (PECVD) on sapphire and then flat GaN thin films were obtained through metal organic chemical vapor deposition (MOCVD) assisted by the sputtering of an AlN buffer layer. Transmission electron microscopy (TEM) showed the existence of low-angle grain boundaries and mainly mixed dislocations at the interface of the epitaxial GaN. As the thickness of the GaN film increased, the number of low-angle grain boundaries dropped by an order of magnitude over the initial 1–3μm. Spectral lines typical of a stress-free GaN film were seen in the low-temperature photoluminescence (PL) measurements, and the TEM analysis corresponded well with the luminescent peaks. These detailed characterizations offer an avenue for a better understanding of the growth behavior of GaN films grown on graphene and furthermore, for obtaining high-quality GaN.

二维材料上三维 (3D) 半导体的范德华外延 (vdWE) 具有整合两者独特优势的广阔前景。在这项研究中，多层石墨烯 (MLG) 通过等离子体增强化学气相沉积 (PECVD) 在蓝宝石上合成，然后通过金属有机化学气相沉积 (MOCVD) 在 AlN 缓冲层的溅射辅助下获得平坦的 GaN 薄膜。透射电子显微镜 (TEM) 显示在外延 GaN 的界面处存在小角度晶界和主要混合位错。随着 GaN 薄膜厚度的增加，小角度晶界的数量在最初的 1-3 μ 范围内下降了一个数量级米。在低温光致发光 (PL) 测量中可以看到典型的无应力 GaN 膜的光谱线，并且 TEM 分析与发光峰很好地对应。这些详细的表征为更好地了解在石墨烯上生长的 GaN 薄膜的生长行为以及获得高质量 GaN 提供了一条途径。