Stacking-dependent and electric field-driven electronic properties and band alignment transitions in γ-GeSe/Ga₂SSe heterostructures: a first-principles study

In this work, we present a comprehensive investigation into the electronic properties and contact behavior of γ-GeSe/Ga₂SSe heterostructures using first-principles calculations. Two stacking configurations, γ-GeSe/SGa₂Se and γ-GeSe/SeGa₂S, are explored, both exhibiting semiconducting behavior with type-II and type-I band alignments, respectively. Notably, our results show that the band alignment transition in these heterostructures can occur spontaneously by simply altering the stacking configuration, eliminating the need for external factors. Additionally, the electronic properties of these heterostructures are highly tunable with an applied electric field, further enabling transitions between type-I and type-II alignments. Specifically, a positive electric field induces a transition from type-II to type-I alignment in the γ-GeSe/SGa₂Se heterostructure, while a negative field drives the reverse transition in the γ-GeSe/SeGa₂S heterostructure. Our findings underscore the potential of γ-GeSe/Ga₂SSe heterostructures for diverse applications, where the tunability of electronic properties is crucial for optimizing device performance.