Effect of Shear Deformation on Electrical and Optical Properties of Graphene Adsorbed Si Atom
The first-principles method based on the density functional theory (DFT) studies the electrical and optical properties of the grapheneadsorption Si atom system by shear deformation. Including adsorption energy, energy band, charge transfer, light absorption coefficient and reflectivity. The results of the study show that when the Si atom is adsorbed on the graphene B site, the absolute value of the adsorption energy is the largest and the system is the most stable. The stability of graphene-adsorption Si atoms increases with shear deformation. The degree of shear has little effect on the stability of the system. Adsorption of Si atom can open the graphene band gap, which changes graphene from a metal to a semiconductor. When the shear deformation is greater than 3%, the graphene geometry is distorted. The band gap of the adsorption system first increases and then decreases as the shear deformation increases. The adsorption systems are all indirect band gaps with band gap values less than 0.3 eV, corresponding to narrow band gap semiconductors. The number of charge populations indicates that covalent bonds and ionic bonds coexist in the adsorption system. The adsorption of Si atom increases the charge transfer between Si and C, but the degree of shear has little effect on charge transfer. In the study of optical properties, the absorption coefficient and reflectance of the shear deformation-induced adsorption system were reduced compared with the shear-induced adsorption system, and the blue-shift phenomenon appeared with the increase of the shear deformation.
Gui Li-Liu,Chao Qun-Yu