An ab initio study of the interaction of graphene and silicene with one-, two-, and three-layer planar silicon carbide

Abstract

Structural, energy and electronic properties of two-dimensional semiconductors are found to differ from those inherent in natural ones, due to sp2 hybridization caused by a decrease in thickness down to the atomic scale. Hybrid 2D semiconductors can combine unique properties of each component, which makes them promising materials for application in electronics, energy storage devices, sensors and catalysts. The unique properties of such semiconductors appear not only due to the effect of size reduction or transition to the discharge of nanoscale objects, but also due to the modification of the electronic structure. In this work, on the basis of DFT calculations, we investigate the geometrical and electronic structures of two hybrid two-dimensional semiconductors created by combining graphene or silicene with silicon carbide, consisting of 1–3 layers. The geometric and energy characteristics of the systems are calculated, and the dependence of the structural parameters, as well as the band structure and density of electronic states, on the number of layers present in silicon carbide are determined. In the “graphene- SiC” system, in the presence of 1–3 layer silicon carbide, a very narrow band gap opens (0.015–0.022 eV). For the “silicene on one- and two-layer silicon carbide” system, a small band gap also appears (0.047 and 0.078 eV, respectively). In the presence of silicene and three layers of silicon carbide in the system, the direct band gap becomes the indirect one. Silicene, in contrast to graphene, shows a high sensitivity to the thickness of the adjacent silicon carbide.