First principles study of fluorine substitution on two-dimensional germanane

Abstract

Using first principles calculations with hybrid exchange-correlation functional, we investigate the electronic structure of germanane and fluorinated germanane. We find that the band gap of fluorinated germanane decreases with the increasing of fluorine coverage, regardless of fluorine distribution on the surface. Our results indicate that chemical functionalization could be used easily to control the band gap of the germanane from 1.55 eV (pure germanane) to 0.17 eV (fully fluorinated germanane). It also shows good potentiality as a photocatalytic material for water splitting, as well as a two-dimensional functional material for optoelectronic and sensing applications.