Engineering the electronic properties of siligraphene sheets by organic molecules: a density functional theory investigation

Abstract

The effect of molecular adsorption on the electronic properties of siligraphene sheets is investigated through density functional theory (DFT) calculations. Adsorption of the organic molecules tetracyanoethylene (TCNE), tetrathiafulvalene (TTF), as well as tetracyanoquinodimethane (TCNQ) on siligraphene (SiC x with x = 1, 2, 3, 5 and 7) is studied. The three types of SiC x : SiC, SiC2 and SiC7 have semiconductor properties, while SiC3 and SiC5 are semimetals. P-type and n-type semiconductors are obtained via charge transfer between the organic molecules and SiCx sheets. The SiC, SiC2 and SiC7 sheets exhibit p-type semiconductor behaviour after TCNE and TCNQ adsorption, while they exhibit n-type semiconductor behaviour due to TTF adsorption. The adsorbed molecules have no significant effect on the band gap energy of SiC3 and SiC5. The results provide an effective method to model the electronic properties of siligraphene sheets.