THE GRAPHENE-SiC SUBSTRATE INTERACTION ENHANCED NEAR-INFRARED ABSORPTION

When epitaxially grown on silicon carbide, a single layer graphene will exhibit a finite energy bandgap like a conventional semiconductor, and its energy dispersion is no longer linear in momentum space in the low energy regime. In this paper, we present a quantitative analysis on the effect of the SiC substrate in the optical absorption of pi-electrons in graphene. We calculated the absorption matrix element and the optical absorption in the near infrared even to the visible region by taking into account the SiC substrate effect. It has been found that the substrate effect can significantly enhance the optical absorption in graphene in the near-infrared region, even by upto 90%. It may be helpful to eliminate the previous discrepancy of optical transmission between the theoretical results and the experimental results in the near-infrared to the visible region.