First-principles study of the electronic and optical properties of nitrogen and gold co-doped graphene

Based on first-principles calculations in the framework of density functional theory, we have systematically studied the electrical and optical properties of substitutional N-doped (N(x)G), Au-doped (Au(x)G) and N-Au co-doped graphene (N(x)Au(x)G) at different doping concentration. It is found that N(x)G and Au(x)G exhibit metal properties, whereas N(x)Au(x)G exhibit semiconductor properties; Irrespective of doping concentration, the transparency of AuxG and N(x)Au(x)G systems may decrease in the frequency interval of 7.0-9.0 eV as the result of having the higher reflectivity and adsorption coefficient. Meanwhile, they can adsorb the spectra of specific wavelengths region in the frequency window of 7.0-10.0 eV which locates the ultraviolet range and the intensity of absorption can be effectively tuned by the doping concentration. These results can serve as useful references for the application of optoelectronic devices.