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 gamma-GeSe/Ga2SSe heterostructures using first-principles calculations. Two stacking configurations, gamma-GeSe/SGa2Se and gamma-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 gamma-GeSe/SGa2Se heterostructure, while a negative field drives the reverse transition in the gamma-GeSe/SeGa2S heterostructure. Our findings underscore the potential of gamma-GeSe/Ga2SSe heterostructures for diverse applications, where the tunability of electronic properties is crucial for optimizing device performance.