Van der Waals heterostructures of Janus XSeTe (X = Mo, W) and arsenene monolayers: A first principles study

Van der Waals heterostructures with unique electronic and optical properties provide many opportunities for two-dimensional materials in the field of optoelectronic devices. In this work, we have constructed XSeTe/arsenene (X = W, Mo) heterostructures based on density functional theory (DFT), and investigated their structural, electronic as well as optical properties via first-principles calculations. The results indicate that the electronic band structures of the Janus XSeTe and arsenene layers are well preserved in these heterostructures through weak van der Waals forces. It is found that the band distribution of the heterostructure can be effectively tuned under biaxial strains or applied electric fields, which induced the conversion from band alignment of type I to type II, and transition of the band gap type from semiconductor to metal for the XSeTe/arsenene (X = W, Mo) heterostructures. In addition, the spin-orbit coupling (SOC) effect on the energy band of XSeTe/arsenene heterostructure is also considered here. Moreover, the absorption coefficients of XSeTe/arsenene heterostructures are improved in the visible and ultraviolet wavelength regions. Therefore, these research results demonstrate that XSeTe/arsenene (X = W, Mo) heterostructures can provide important guidance for exploring the physical properties of low-dimensional optoelectronic and electronic devices.