Band structures of carbon and silicon 2D supracrystals

Background. Unique properties of graphene, in particular its exceptionally high electrical and thermal conductivity, lead some researchers to the conclusion that the carbon electronics is taking the place of the classical silicon electronics. The purpose of this paper is to compare electronic properties of different carbon and silicon $sp^2$-nanoallotropes whether to confirm or refute this conclusion. Materials and methods. Supracrystalline carbon and silicon $sp^2$-nanoallotropes of the types (X)$_{44}$, (X)$_{63(12)}$ and (X)$_{664}$ are studied in the work. The calculations were carried out both by tight-binding approximation (the TB method) and by the density functional theory formalism (the DFT method) using the VASP package. Results. It is shown that for both carbon and silicon the (X)$_{44}$ and (X)$_{63(12)}$ structures are semimetals, and the (X)$_{664}$ structure is a narrow-band semiconductor. Conclusions. The carbon $sp^2$-nanoallotropes really seem to be more promising materials for nanoelectronics than the analogous silicon nanoallotropes. Similar two-dimensional carbon and silicon nanoallotropes can be useful for nanoelectronics, nanophotonics, and nanooptoelectronics.