Ab initiostudies of isolated boron substitutional defects ingraphane

Abstract

We have systematically studied energetics, structural and electronic properties of \ndi erent con gurations of the B atoms substituting C-H pairs located on a single hexagonal \nring in a graphane system using the rst-principles density functional theory (DFT). A total \nnumber of 12 distinct B dopants con gurations were identi ed and characterized. Based on \nthe formation energy analysis, we found that relative stability of B dopants depends greatly on \nthe defect con gurations. Our results suggest that the B substitutions prefer to be distributed \nrandomly but avoiding the formation of homo-elemental B-B bonds in a graphane system, at \nany concentration. Generally, the values of band gap decrease as the number of B dopants \nincreases, but the low energy con gurations have large band gaps compared to those that have \nhomo-elemental bonds. As a result, the band gap of graphane can be ne tuned through \nthe change in the structural arrangement of B atoms. The adequate control of the electronic \nstructure of graphane through doping should be essential for technological device applications.