Synthesis And Characterzation Of ?-MnSe Nanoplates And ?-MnSe/WS₂ Vertical P-N Junction

In recent years,with the gradual deepening of two-dimensional(2D)materials,people have gradually discovered the full range of physical properties of two-dimensional materials family,from graphene conductors to Mo S₂ semiconductors to insulating h-BN,generating many exciting new physical discoveries.Due to the novel properties of two-dimensional atomic semiconductor materials and their heterostructures,they have potential applications in the construction of a new generation of highly compact electronic and optoelectronic devices.However,at present,the synthesis of two-dimensional nanostructures is mainly limited to natural layered materials which has been studied relatively thoroughly.Emerging 2D non-layered materials(2D NLMs),which combine the excellent properties of bulk materials with the advantages of 2D geometry,have provided a broad opportunity for the design of next-generation optoelectronic devices.However,unlike layered materials,these materials generally tend to stack into three-dimensional(3D)structures due to the lack of a two-dimensional anisotropic growth drive.Therefore,it is a key challenge to precisely control the growth of non-layered ultra-thin nanocrystals.Moreover,there are many intrinsic P-type two-dimensional semiconductors among the non-layered semiconductor family.In the past decade,P-type two-dimensional materials are rarely studied.Therefore,it is an important breakthrough for the research of two-dimensional P-type semiconductors to directly grow and synthesize P-type semiconductors,which will not only expand the two-dimensional P-type semiconductor family,but also make for the discovery of other new two-dimensional P-type semiconductors.In addition,the semiconductor P-N junction is the basis of the most advanced optoelectronic architecture.Therefore,the exploration of the emerging two-dimensional P-type semiconductors is conducive to the preparation and study of two-dimensional P-N junctions.Therefore,it is of great significance to broaden the two-dimensional p-type semiconductor,to explore the anisotropic growth of non-layered materials and to study the electronic and optoelectronic properties of two-dimensional non-layered materials.So,this paper mainly carried out the following work:(1)The large area of ultra-thin two-dimensional non-layered p-type?-MnSe semiconductor was epitaxial grown on mica by a salt-assisted van der Waals epitaxy(VDWE)method.By increasing the carrier gas flow,the thickness of?-MnSe nanosheets can be systematically reduced from more than 150 nm to 0.9 nm.Raman spectroscopy,X-ray diffraction,transmission electron microscopy and electron diffraction studies confirmed that the obtained 2D nanosheets are single crystal with high quality.The response time of the photodetector based on p-type?-MnSe nanosheets can be as low as 4 ms.(2)?-MnSe/WS₂ heterostructure was also prepared by physical vapor deposition(PVD)and VDWE two-step synthesis method.The diodes based on p-type?-MNSE and n-type WS₂ have excellent optical detection performance(1.00×10¹³ Jones),high optical responsiveness(49.1 A W^–1)and obvious rectification ratio(283).