The structural, electronic and optical properties of four α-Se-based heterostructures with hyperbolic characteristics

The physical properties and potential applications of two-dimensional (2D) materials can be effectively modulated and enriched by constructing van der Waals heterostructures (VDWHs) with two or more 2D monolayer materials. In this work, by using first-principles calculations based on density functional theory (DFT), we have systematically investigated the structural, electronic and optical properties of four alpha-Se-based VDWHs, that is, alpha-Se/Ca(OH)(2), alpha-Se/GaSe, alpha-Se/h-BN and alpha-Se/MoS2 VDWHs. The results show that both the band alignment and band gap of these four VDWHs can be effectively modulated by interlayer coupling, biaxial strain and an external electric field. Compared with interlayer coupling and biaxial strain, the external electric field can modulate the electronic properties of these VDWHs more significantly, which makes them exhibit more rich electronic properties. Interestingly, the optical property calculations revealed that both alpha-Se and the four alpha-Se-based VDWHs have intrinsic hyperbolic properties. In addition, compared with the individual components, the optical absorption of these four VDWHs in the visible and ultraviolet light regions is significantly enhanced. These results enrich the properties of selenene and selenene-based VDWHs and extend their potential applications in electronic and optoelectronic devices.

Automated summary

In this work, the structural, electronic, and optical properties of four alpha-Se-based VDWHs were systematically investigated using first-principles calculations based on density functional theory. The results showed that the electronic properties and optical absorption of these VDWHs can be effectively modulated by interlayer coupling, biaxial strain, and an external electric field, enhancing their potential applications in electronic and optoelectronic devices.