Effect of graphene domains orientation on quasi van der Waals epitaxy of GaN

Abstract

We demonstrate the growth features of III-nitrides on graphene buffer layers obtained by the CVD method on a copper catalyst with different dominant grain orientations. The reflection high-energy electron diffraction technique (RHEED) is used to map the 2D reciprocal space structures of graphene buffers and growing nitride layers. The RHEED reciprocal space pattern for the graphene layer grown on a (111) textured copper foil and transferred to a SiO2/Si substrate demonstrates the sixfold symmetry characteristic of a highly oriented material. In turn, graphene grown on a Cu (100) foil consists of two types of domains that are 30° rotated relative to each other. It has also been demonstrated that III-nitride films exactly repeat the texture of the 2D graphene buffers. The GaN sample grown over the highly textured substrate demonstrates a clear sixfold symmetry of the RHEED reciprocal space map as well as {101¯3} XRD pole figure, which is close to 2D surface morphology. In turn, the GaN film grown over the graphene buffer layer transferred from the Cu (100) textured foil has 12-fold axial symmetry, which is equivalent to the essentially two-domain in-plane orientation of the initial graphene.