Theoretical Study Of The Electronic Properties Of Two-Dimensional AlAs/InSe And GeC/BAs Heterojunctions

With the successful stripping of graphene,the unique electronic,optical,thermal and mechanical properties of two-dimensional materials make them have a wide range of application prospects and have been highly valued by all walks of life.Due to the quantum confinement effect along the out-of-plane direction,two-dimensional materials tend to exhibit unique characteristics that differ from volumetric materials.In addition to graphene,many two-dimensional materials,such as hexagonal boron nitride（BN）,transition metal oxides（Zn O and Ti O₂）,transition metal dihalides,and phosphoric acid,have been extensively explored and are expected to realize their potential in various fields.However,a single two-dimensional material has many drawbacks that cannot be overcome.In recent years,researchers have been interested in semiconductor heterostructures,which are assembled from two semiconductors with different lattice structures,electronic properties,or chemical compositions,and which lay the foundation for modern electronics.In the process of designing heterogeneous structures,bending or hybridizing the electron strip structure of the two components causes charge transfer at the interface and generates a built-in electric field at the interface,which is particularly efficient for optoelectronic gap separation and facilitates the development of high-performance optoelectronic devices.In this project,the geometry,electronic properties and optical properties of AlAs/InSe and GeC/BAs heterostructures were explored using first-principles computational methods.The geometry,electronic properties and optical properties of the AlAs/InSe heterostructure were studied by applying an external electric field and strain.The results show that the AlAs/InSe heterostructure has a typical Type-II band arrangement and an indirect band gap of1.28 e V.When we adjust the layer spacing or apply an external electric field and strain,we can effectively change the band gap value of the heterogeneous structure.Interestingly,when an electric field of 0.5 V/?is applied,the heterostructure achieves a transition from Type-II to Type-I.In addition,the absorbance of AlAs/InSe heterostructures is significantly improved compared to isolated monolayers,especially in the ultraviolet region.In summary,our results show that novel two-dimensional AlAs/InSe heterojunctions can be strong candidates for optoelectronic materials and nanodevices.The electronic properties of GeC/BAs heterostructures were systematically studied through first-principles calculations,and the physical mechanism of their properties being modulated by strain and electric field was discussed.Our results show that this heterostructure has an inherent Type-II band arrangement and direct band gap.The band gap of the GeC/BAs heterostructure decreases significantly with the increase of biaxial strain,further enhancing the photoexcited electron transition.Under the appropriate applied electric field,there is a Stark effect in the band gap due to spontaneous polarization in the van der Waals heterogeneous structure.In addition,the calculated light absorption curve shows that the GeC/BAs heterostructure can exhibit good visible light absorption performance.We also consider the effects of different biaxial strains and applied electric fields on the optical properties of GeC/BAs heterostructures,and find that they can effectively modulate the optical properties.Therefore,GeC/BAs heterostructures have potential applications in solar cells,nanoelectronics and optoelectronics.