Germanium monosulfide monolayer: a novel two-dimensional semiconductor with a high carrier mobility

Abstract

Low-dimensional semiconducting materials with moderate band gaps as well as high carrier mobilities are highly sought for future application in microelectronics. By means of hybrid density functional theory computations, we predicted that a novel two-dimensional (2D) IV–VI material, namely germanium monosulfide (GeS) monolayer, is a rather desirable candidate. According to our computations, GeS monolayer is semiconducting with an indirect band gap of 2.34 eV, which can be effectively tuned by employing an external strain. Remarkably, the GeS monolayer has an electron mobility of 3680 cm² V⁻¹ s⁻¹, which is much higher than that of MoS₂ monolayer. Our computations also revealed that GeS monolayer is a stable structure and can be obtained by exfoliation or mechanical cleavage techniques. These findings render GeS monolayer a promising 2D material for applications in future microelectronics, and call for more research attention on 2D IV–VI materials.