Band-gap engineering of graphene by Al doping and adsorption of Be and Br on impurity: A computational study

Abstract Graphene, being a gapless semiconductor, cannot be used in pristine form for optoelectronic applications such as solar cells. Therefore, it is necessary to tune a band-gap in pristine graphene. Density functional theory calculations have been performed to investigate the structural, electronic, and charge transfer mechanism of different impurities doped/adsorbed in graphene sheet. The results indicate that Al and Be doping can significantly modify the structural and electronic properties of graphene. Replacement of single C atom with Al atom induces a band-gap of 0.40 eV. Adopting different arrangements of Al, Be and Br employing doping and adsorption techniques we computed a variety of band-gap values, maximum value being 0.82 eV. Badar charge analysis indicates that the valence charge transmission takes place from less electronegative atoms towards atoms having higher electronegativity. The adsorption/doping of impurity atoms induce band-gap values in a significant wide range, which seems sufficient for its use in optoelectronic devices. Our results offer the opportunity to tune the electronic band structure of graphene for desired applications.