The germanium telluride monolayer: a two dimensional semiconductor with high carrier mobility for photocatalytic water splitting

Abstract

Photocatalytic water splitting represents the most promising approach to convert solar energy into chemical energy, and numerous efforts have been devoted to seeking photocatalysts that can work under visible-light irradiation to efficiently harvest solar energy. Here, by means of density functional theory computations, we predicted that the two dimensional germanium telluride (GeTe) monolayer can be easily exfoliated from the bulk phase by overcoming a small cleavage energy of ∼0.63 J m⁻². The GeTe monolayer is semiconducting with a considerable band gap of 2.35 eV and shows suitable band edge positions for photocatalytic water splitting. Remarkably, the GeTe monolayer exhibits rather high electron and hole mobilities and has pronounced optical absorption in the visible region of the solar spectrum. These excellent properties render the GeTe monolayer a promising photocatalyst for water splitting.