Novel wide spectrum light absorber heterostructures based on hBN/In(Ga)Te

Abstract

Two-dimensional group III monochalcogenides have recently attracted quite attention for their wide spectrum of optical and electric properties, being promising candidates for optoelectronic and novel electrical applications. However, in their pristine form they are extremely sensitive and vulnerable to oxygen in air and need good mechanical protection and passivization. In this work we modeled and studied two newly designed van der Waals (vdW) heterostructures based on layer of hexagonal boron nitride (hBN) and GaTe or InTe monolayer. Using density functional theory, we investigate electronic and optical properties of those structures. Their moderate band gap and excellent absorption coefficient makes them ideal candidate for broad spectrum absorbers, covering all from part of IR to far UV spectrum, with particularly good absorption of UV light. The hBN layer, which can be beneficial for protection of sensitive GaTe and InTe, does not only preserve their optical properties but also enhances it by changing the band gap width and enhancing absorption in low-energy part of spectrum. Calculated binding energies prove that all three stacking types are possible to obtain experimentally, with H-top as the preferable stacking position. Moreover, it is shown that type of stacking does not affect any relevant properties and bandstructure does not reveal any significant change for each stacking type.