First-principles Study On Of Photoelectric Properties Of Two-dimensional GeS/ Phosphorene Heterojunctions

Since the advent of Graphene at the beginning of the 21 st century,two-dimensional materials have rapidly become a research hotspot in the field of low dimensional nanomaterials due to their excellent physical properties.Various new two-dimensional materials such as h-BN,Mo S2,and phosphorene have been successfully prepared in experiments.Among these materials,the two-dimensional IV/VI group monosulfide compound MX(M=Sn,Ge;X=Se,S,Te)stands out as a black phosphorus material with a structure similar to that of phosphenes.Due to its suitable bandgap,high carrier mobility,and abundant Earth reserves,it has broad application prospects in fields such as solar cells and optoelectronic converters.In this paper,based on the lattice characteristics and experimental research progress of the layered Ⅳ/Ⅵ group single sulfur compound MX,the structural,electronic and optical properties of GeS/phosphorene transverse and vertical heterostructures based on GeS and phosphorene are systematically studied by using the first principle calculation based on Density functional theory.(1)Firstly,we studied the GeS/ phosphorene lateral heterojunction.The results indicate that this special type of heterojunction can stably exist along the direction of the one-dimensional interface of the armrest type.The lattice mismatch and formation energy of these heterostructures are very small,and they show excellent stability near the interface through Covalent bond.These characteristics are very conducive to the epitaxial growth of heterojunction structures.By effectively adjusting the size and composition ratio of heterojunction structures,their electronic and optical properties can be effectively adjusted.(2)Considering the different splicing methods of two-dimensional materials,single-layer GeS and phosphorene were stacked vertically to construct a GeS/phosphorene vertical heterojunction(van der Waals heterojunction).The optical and electronic properties of GeS/phosphorene vertical heterojunction were calculated,including its band structure,band edge arrangement,and light absorption coefficient.By simulating the application of pressure by changing the lattice size and interlayer spacing,the optical and electronic properties of GeS/phosphorene vertical heterojunctions are adjusted.Through calculation,it was determined that the band structure of GeS/phosphorene vertical heterojunction undergoes significant changes under biaxial stress,while its optical properties remain stable,indicating its potential in photovoltaic applications.