The Research About Photoelectric Properties Of 2D FePS₃ And Its Heterojunction

Since the discovery of graphene in 2004,two-dimensional（2D）van der Waals layered materials have received extensive attention from the scientific community.These include single-element materials graphene,black phosphorus,germanene,etc.,dual-element materials transition metal chalcogenides（TMDC）,boron nitride,Cr I ₃,etc.,and three-element materials metal-phosphorus-trichalcogenide（such as FePS₃）etc.These materials exhibit excellent electrical,optical,and magnetic properties at the 2D scale,providing a new direction for the study of next-generation optoelectronic and magnetoelectric devices with high response and low power consumption.Since there are no dangling bonds on the surface of 2D materials,it is possible to break through the limitation of lattice matching,and stack different 2D materials to form van der Waals heterojunctions with different energy band arrangements,thereby realizing broadband and high-performance photodetectors.FePS₃ is a wide-bandgap,antiferromagnetic material that exhibits excellent UV photodetection performance,while the magnetic proximity effect is observed by formi ng a heterojunction with ferromagnetic materials.However,the current research on the photodetector of FePS ₃heterojunction is relatively scarce,which restricts the further exploration of the photodetection performance of this material.In this paper,we mainly study the optoelectronic properties of FePS₃ and its heterojunction and analyze the reasons for the better optoelectronic properties of the heterojunction.The main research contents are as follows:（1）High-quality FePS₃ nanosheets were obtained by traditional chemical vapor transport and mechanical exfoliation method s,and FePS₃ field effect transistors were prepared.The electrical test showed that FePS ₃ is a p-type semiconductor material.（2）Two heterojunctions of SnS₂/FePS₃ and SnS₂/FePS₃/Gr were formed by stacking p-type FePS₃,n-type SnS₂ and graphene（Gr）by dry transfer method.Electrical tests show that both heterojunctions exhibit unidirectionally conducting PN junction characteristics,differing in the dominant carrier type involved in c onduction.（3）The photoresponse of SnS₂/FePS₃ and SnS₂/FePS₃/Gr heterojunctions at different laser wavelengths and powers were tested.The SnS ₂/FePS_3/Gr heterojunction exhibits 405-850 nm broadband photoresponse.The photoelectric response of SnS₂/FePS₃/Gr heterojunction is better than SnS ₂/FePS₃,SnS₂ and FePS₃.Theoretical calculation and carrier transport mode analysis shows the high responsivity and short response time of SnS₂/FePS₃/Gr heterojunction should be attributed to the type II band alignment by SnS₂ and FePS₃formed and shorter channel length,which makes electrons and holes can be separated and transported quickly.The results of this study provide more options for realizing high-performance,broadband photodetectors.