A Raman imaging study of growth process of few-layer epitaxial graphene on vicinal 6H–SiC

Abstract

Few-layer epitaxial graphenes grown on vicinal 6H–SiC (0001) were characterized by confocal Raman imaging. In the beginning of the growth, the surface of SiC substrate was covered with monolayer graphene. Next, few-layer graphenes started to grow toward directions perpendicular to [11–20] of the SiC substrate. The shift in the G-peak was not straightforward with the increase in number of graphene layers. This result can be interpreted that the in-plane compressive stress from the substrate depends on the domain size of graphene. The 2D-peak frequency shifted to higher frequency side due to strong compressive strain from the substrate with increasing of the growth times.