Studies On The Photodetectors Based On Two-dimensional ReS₂ And Its Heterostructure

Transition metal chalcogenides have attracted more attention due to their unique properties.Rhenium disulfide is one of them and suitable for light detection.In this thesis,the potential of ReS₂ and its heterostructures in photodetectors was studied.Two-dimensional ReS₂sheets have been fabricated by mechanical exfoliation.Their thickness was measured by atomic force microscope.The dependence of the R value of the optical image of the sample on the number of layers is concluded,which can be used to measure the number of layers of thin ReS₂sheets.The flexible photodetector based on ReS₂was fabricated by transferring a ReS₂sheet onto Au electrodes,and its performance was measured.ReS₂has obvious response to visible light.At a bias of 3V,the maximum responsivity and external quantum efficiency of the photodetector are 53.3A/W and 10140%,respectively.The response/recovery time is 700/900ms.The photodetector is flexible.The shortcomings of the photodetector are high dark current and low on-off ratio.Heterostructures have excellent properties better than its components and have been widely used in various devices.ReS₂/Mo S₂ and ReS₂/Ga Se heterostructures have been fabricated and characterized.It is of great significance to explore the influence of heterostructure on its optoelectric performance.It is found that the dark current values of ReS₂,Mo S₂and ReS₂/Mo S₂are high at 2V,resulting in low sensitivity.At 0V,ReS₂,Mo S₂and ReS₂/Mo S₂have response to visible light.However,Mo S₂has the highest response to visible light,indicating this heterostructure is unsuitable for light detection.The ReS₂/Ga Se heterostructure was constructed by using ReS₂ and Ga Se.Under the same conditions,the optoelectric performance of ReS₂/Ga Se heterostructure is better than that of ReS₂ and Ga Se.At 2V,the responsivity and external quantum efficiency of the heterostructure are 0.27A/W and 74%respectively,its on-off ratio is 132,and the response/recovery time is 9ms.In conclusion,the ReS₂/Ga Se heterostructure has potential applications in the field of photodetection.