Interlayer coupling and external electric field tunable electronic properties of a 2D type-I α-tellurene/MoS2 heterostructure

α-Tellurene, a recently theoretically and experimentally accessible Group-VI two-dimensional (2D) material, has attracted considerable attention. Owing to its unique structure being similar to that of 2D transition metal dichalcogenides (TMDs), the studies of 2D van der Waals heterostructures (vdWHs) based on α-tellurene/TMDs will be very interesting. In this work, we designed an α-tellurene/MoS 2 vdWH and investigated its electronic properties by using the first-principles method. Our results have suggested that such an α-tellurene/MoS 2 vdWH possesses an obvious type-I band alignment with an indirect band gap of approximately 0.77 eV. Moreover, we have also found that an intriguing type-I to type-II or indirect to nearly direct transition can be induced by increasing the interlayer coupling of the heterostructure or applying an external electric field. Overall, these findings provide a promising route to tune the electronic properties and design new α-tellurene-based vdWHs for applications in electronic and optoelectronic devices. Applying an external electric field can induce a transition from a type-I to a type-II band alignment in an α-tellurene/MoS 2 heterostructure.