The effect of impurities in ultra-thin hydrogenated silicene and germanene: a first principles study.

Spin polarized density functional theory within the GGA-PBE and HSE06 approach for the exchange correlation term has been used to investigate the stability and electronic properties of nitrogen and boron impurities in single layers of silicane and germanane. We have observed that these impurities have lower formation energies in silicane and germanane when compared to their counterparts in graphane. We have also noticed that the adsorption of H atoms in the vicinity of defects stabilizes the system. In addition, we have shown that the electronic properties of silicane and germanane can be tuned when N and B are incorporated in the Si and Ge network. N-doping and B-doping give rise to n-type and p-type semiconductor properties. However, the adsorption of H atoms quenches the doping effects.