First-Principles Study of Strain Engineered Electronic Properties of GeSe-SnS Hetero-bilayer

Abstract

Vertical stacking of two dimensional (2D) materials is emerging as an exciting method for the design of next generation electronic and optoelectronic devices. Here, we employed first-principles calculations based on density functional theory to study the structural and electronic properties of the GeSe-SnS Van der Waals hetero-bilayer. Our results suggest that this hetero-bilayer is semiconducting in nature with a direct band gap of 0.9006 eV and also has an intrinsic type-II band alignment indicating an expectation for spontaneous electron-hole charge separation. The electronic responses of the hetero-bilayer are found to be sensitive and anisotropic to the applied strain. The direct band gap of the GeSe-SnS hetero-bilayer is tunable by strain within a considerable range (0.306–1.197 eV) and the transitions between direct–indirect band gap can repeatedly be obtained by applying compressive uniaxial and biaxial strains. The carrier effective masses of the hetero-bilayer can also be engineered by strain in a low mass range. These intriguing results suggest GeSe-SnS hetero-bilayer as a good candidate for applications in electronic and optoelectronic semiconductor devices.