Enhanced carrier mobility and tunable electronic properties in α-tellurene monolayer via an α-tellurene and h-BN heterostructure

Abstract

Using first-principles calculations within density functional theory, we explore the electronic properties of the α-tellurene/h-BN (Te/BN) heterostructure. We find that the type-I van der Waals (vdW) Te/BN bilayer exhibits an indirect semiconductor property with a bandgap of 0.59 eV, in which both the valence band maximum and conduction band minimum originate from the tellurene monolayer. The very weak interaction between α-tellurene and h-BN monolayers is demonstrated by the small charge transfer between the interlayer. More strikingly, we find that the carrier mobilities in the Te/BN bilayer can reach up to 10⁴ cm² s⁻¹ V⁻¹, one order of magnitude larger than those in tellurene. The underlying physics is that the Te/BN bilayer dramatically increases the in-plane stiffness as well as reducing the deformation potential compared with the tellurene monolayer. Additionally, we also show that the electronic properties of the Te/BN bilayer can easily be tuned by introducing defects or dopants in the BN monolayer. For instance, the B vacancy makes the Te/BN bilayer undergo the transition from semiconductor to half-metal. Our findings will broaden the potential application of tellurene and provide theoretical guidance for the relative experimental studies on 2D heterobilayers.