Abstract
Abstract
The recent experimental synthesis of the monolayer γ-GeSe, characterized by its unique Mexican-hat band dispersion, has attracted considerable research interest. However, the exploration of band gap engineering in bilayer γ-GeSe and γ-SnSe through the application of strain and electric fields remains under-investigated. In this study, we demonstrate that both strain and electric fields are effective methods for band gap engineering in bilayer γ-GeSe and γ-SnSe. We have discovered that strain can not only tune the band gap but also induce a transition from an indirect to a direct band gap. Furthermore, it is observed that the band gap of bilayer γ-GeSe and γ-SnSe can be modulated by an electric field, potentially leading to a transition from semiconductor to metal. Our findings suggest that band gap engineering via strain and electric fields is a promising approach for designing nanoelectronic and optoelectronic devices based on bilayer γ-GeSe and γ-SnSe.