Gate-controlled rectification and high photoresponse performance in two-dimensional non-layered α-MnSe/transition metal chalcogenide heterostructures

Abstract

Owing to its excellent p-type semiconductor characteristics, manganese selenide (MnSe) demonstrates promising potential for high-performance electronic and optoelectronic applications. In this work, we successfully synthesized high-quality two-dimensional (2D) α-MnSe crystals via chemical vapor deposition (CVD). Subsequently, we systematically investigated heterojunctions constructed by integrating CVD-grown non-layered α-MnSe nanosheets with mechanically exfoliated layered MoSe₂ and MoS₂. The α-MnSe/MoSe₂ heterostructure exhibits gate-controlled reversible rectifying behavior. This reversible rectification originates from gate-voltage-modulated Fermi level shifts, which dynamically reconfigure the built-in electric field. Meanwhile, the α-MnSe/MoSe₂ heterostructure exhibits excellent spectral response with a responsivity of 0.23 A W⁻¹ and a detectivity of 1.8 × 10¹² Jones. The α-MnSe/MoS₂ heterojunction exhibits an excellent current on–off ratio of 6800, a high responsivity of 3.17 A W⁻¹ and a detectivity of 4.7 × 10¹¹ Jones. These outstanding performance metrics are attributed to the type-II band alignment and the strong built-in potential at the heterojunction interface, which synergistically facilitate the efficient separation of photo-generated carriers. Furthermore, both the α-MnSe/MoSe₂ and the α-MnSe/MoS₂ heterojunctions exhibit remarkable photovoltaic characteristics, offering new potential for the development of self-powered photodetectors. This study unveils novel functionalities of 2D α-MnSe-based heterostructures for designing high-performance optoelectronic devices.