The Interface Stability And Electronic Properties Of Zr₂CO₂/MoS₂ Heterostructure

To reduce the power consumption and improve the processing speed of photoelectric devices,the photodetectors are gradually developing towards miniaturization and integration.Because of its high specific surface area and high response speed,two-dimensional materials have become a research hotspot in the new generation of electronic and optoelectronic applications.Due to the limitation of material space,high transmittance and low efficiency of electron hole pair separation,the photoelectric conversion efficiency of MoS₂ and Zr₂CO₂ devices is insufficient.Constructing heterostructure has been proved to improve the photoelectric performance of semiconductor.In the work,the stability and electrical properties of Zr₂CO₂/MoS₂heterostructure are studied by density functional theory based on first-principles.In addition,the band modulation of Zr₂CO₂/MoS₂ heterostructure by external electric field is also studied.The research contents are as follows:1.The energy band structures and density of states of Zr₂CO₂ and MoS₂ were calculated to study their electrical properties.The results show that MoS₂ is a direct semiconductor with a band gap of 1.72 e V and Zr₂CO₂ is a direct semiconductor with a band gap of 0.83 e V.Our results show that the electronic structures of Zr₂CO₂ and MoS₂are insensitive to the electric field.2.To improve the electron hole pair separation efficiency of Zr₂CO₂ and MoS₂,Zr₂CO₂/MoS₂ heterostructure was constructed by combining Zr₂CO₂ with MoS₂.The binding energies of Zr₂CO₂/MoS₂ heterostructures with different layer spacing are calculated.The results show that Zr₂CO₂ and MoS₂ can form stable van der Waals force heterostructure.In addition,it is found that the outer oxygen defects can improve the stability of the heterostructure.After the construction of Zr₂CO₂/MoS₂ heterostructure,the built-in electric field from MoS₂ to Zr₂CO₂ is generated,and the conduction band and valence band potential of Zr₂CO₂ layer in the heterostructure are higher than those of MoS₂ layer.Therefore,the Zr₂CO₂/MoS₂ heterostructure obeys the type-II transport mechanism,which can effectively increase the charge transfer efficiency and prolong the carrier lifetime.The VBO,CBO and BG of Zr₂CO₂/MoS₂ heterostructure also change with the change of layer spacing,which proves that the layer spacing can modulate the electronic properties of Zr₂CO₂/MoS₂ heterostructure.3.To improve the photoelectric response ability of Zr₂CO₂/MoS₂ heterostructure,an external electric field was used to modulate the electronic properties of Zr₂CO₂/MoS₂heterostructure.The band gap of Zr₂CO₂/MoS₂ heterostructure changes about 0.2 e V with 0.1 V/?electric field increasing,and the applied vertical electric field can modulate the band gap of the Zr₂CO₂/MoS₂ heterostructure excellently.The further study of charge density difference shows that the interface charge redistribution of Zr₂CO₂/MoS₂ heterostructure is very sensitive to the electric field,which is the reason why the energy band of Zr₂CO₂/MoS₂ heterostructure is sensitive to the electric field.With the increase of electric field,the optical absorption coefficient of Zr₂CO₂/MoS₂heterostructure also increases,which thus enhances the light response ability.Therefore,the application of external electric field improves the performance of Zr₂CO₂/MoS₂heterostructure in the field of photodetectors.