The essential difference between remote epitaxy and van der Waals epitaxy: Long-range orbital hybridization at the GaN/graphene/AlN interface

Abstract

In this article, the growth of GaN nucleation layers on AlN substrates covered with different layers of graphene were achieved by MOCVD, and and the essence of remote epitaxy and van der Waals epitaxy was clarified. It has been shown that the different epitaxy methods were very sensitive to the number of graphene layers. When inserting single and bilayer graphene, the grown GaN grains exhibited single crystal morphology with consistent in-plane orientation. In contrast, distortion angles of less than 1° and 23° occurred between the GaN grains grown on tri- and multilayer graphene. Theoretical calculations indicated that the interfacial binding energy between GaN and graphene decayed nonlinearly with increasing the number of graphene layers. The interatomic orbital hybridization revealed the shielding effect of graphene on AlN polarity.