First-principles Design And Photoelectric Properties Of Two-dimensional α-As/α-AsP Vertical Heterostructures

As a new two-dimensional（2D）material,the 2D V group material has attracted much attention.The V group single element semiconductor arsenene and V-V binary semiconductor arsenic phosphate（As P）have excellent properties such as tunable band gap high carrier mobility,which have potential applications in photoelectric devices and solar cells.However,with the development of two-dimensional material exploration,the deficiency of single material has gradually become prominent,and the construction of heterostructures is a new method to make up for the deficiency of single material and obtain properties.In this paper,based on first principles,the structural stability,electronic and optical properties ofα-As andα-As P heterostructures are studied.The conclusions can be classified as follows:1.Four possible stacking modes are constructed to study the stability of the structure.Firstly,the most stable stacking is determined by the binding energy.Ab initio molecular dynamics simulations and phonon spectra were calculated to further verify the stability of the structure.2.The electronic properties and interfacial charge transfer ofα-As/α-As P heterostructures are calculated.The findings indicated that theα-As/α-As P heterostructures is a kind of semiconductor with an indirect band gap of 0.86 e V,which is smaller than that of monolayer.The charge transfer at theα-As/α-As P interface is calculated fromα-As toα-As P.3.The light absorption coefficient and photoelectric conversion efficiency ofα-As/α-As P heterostructures were calculated.The results show that the light absorption ofα-As/α-As P heterostructures is anisotropic.Moreover,the light absorption coefficient was significantly enhanced,especially up to 10⁶ cm^-1 in the ultraviolet region.The photoelectric conversion efficiency ofα-As/α-As P heterostructures is about 21.3%,which is higher than that of As P/Cd Se（13%）and Ge Se/As P（16%）.At the same time,carrier mobility is calculated.The results show that the mobility ofα-As/α-As P heterostructures can reach 10³ cm²V^-1s^-1.4.The electronic properties ofα-As/α-As P heterostructures are adjusted by strain application.Results suggest that uniaxial strain and biaxial strain show different tunability.It is converted to direct band gap under uniaxial strain and adjusted to gold property under biaxial strain.These results indicate that 2Dα-As/α-As P heterostructures have potential applications in optoelectronic devices and solar cells.