Optoelectronic Device Based On ReS₂ And Its Heterosturctures

Two-dimensional(2D)materials have attracted great attention from researchers in recent years due to its unique properties,such as atomically thin thickness,large specific surface area,quantum confinement effect,etc.At the same time,2D materials are also considered as one of the key materials in the post-Moore era.Through the effect of van der Waals forces between layers,different 2D materials can be stacked together to form a heterostructure,which has a very high degree of freedom and shows great potential in device design,application and integration.Among them,the anisotropic 2D material exhibits richer physical properties due to its low symmetry lattice structure,and its increased degree of freedom for adjusting physical properties which can be used to design unique semiconductor devices and explore new application.Research on anisotropic two-dimensional materials has gradually increased in recent years.However,at present,there is still little work on adjusting the anisotropy of materials,using the characteristics of anisotropic materials and the combination of isotropic materials and continuing to study the anisotropy of their heterostructures.Based on this,we selected rhenium disulfide with a 1T' phase structure,and selected tungsten disulfide to construct a van der Waals heterojunction with it.We have conducted research on anisotropy and optoelectronics around rhenium disulfide and its heterojunction.1.According to photoluminescence spectroscopy,we found that the exciton peak shifts of rhenium disulfide with different layer thicknesses have little difference,which indicates the weak interlayer coupling between rhenium disulfide.Rhenium disulfide field-effect transistors with different layer thicknesses were prepared,which can show the properties of semiconductor and semi-metal respectively.2.The type II van der Waals heterostructure based on the isotropic material tungsten disulfide and the anisotropic material rhenium disulfide was prepared.By using Raman spectroscopy and photoluminescence spectroscopy,it was observed that the Raman peak intensity of rhenium disulfide was reduced after the heterostructure construction,and the exciton peak of tungsten disulfide was quenched apparently,confirming the coupling effect between layers.By using different metal contact electrodes,rhenium disulfide and tungsten disulfide heterostructures exhibit different electrical properties.When the titanium-gold electrode is used,the heterostructure exhibits bipolarity.When the gold electrode and the indium-gold electrode are used directly,the heterostructure-based device exhibits n-type characteristics.At the same time,we studied the anisotropy of rhenium disulfide and its heterostructure with tungsten disulfide.By angle-resolved polarized Raman spectroscopy,we have studied the polarized Raman peaks of rhenium disulfide and its heterostructure.Regardless of whether it is rhenium disulfide or heterostructure,its Raman intensity changes periodically with the rotation angle,with a period of 180°,which is centered on symmetry.However,compared with rhenium disulfide,the anisotropy ratio of the heterostructure has changed,which provides a new research direction for controlling the anisotropy of materials.