Based On Two-dimensional Material Heterojunction Polarization Sensitive Photodetector Experiment And Mechanism Research

As we know,polarized light detection is an important branch in the field of light detectors.The different polarization sensitivity characteristics of light detectors can be used to distinguish the detection target from the background more effectively.However,due to the lack of inherent polarization absorption characteristics of many two-dimensional materials,it is still a great challenge to develop high-performance polarized photoelectric detectors.This paper describes a photodetector based on the vertical structure of the ReSe2/WSe2 van der Waals heterojunction.The photodetector is illuminated with a 520nm wavelength laser at room temperature,with a response rate of 0.28 AW-1 and a detection rate of up to 1.1×1012 Jones.It is worth noting that 2D transition metal chalcogenides have excellent photoelectric properties,among which the representative material Tungsten selenide has the lowest known thermal conductivity in the world at present.Rhenium selenide is also a new type of transition metal sulfide,characterized by low lattice symmetry and interlayer coupling.As an optical biaxial material,the polarization detection of the device in different directions can be realized due to its unique internal structure.To explore the photoelectric detection performance of ReSe2/WSe2 heterojunction,this paper mainly conducts experiments centering on the thin layer preparation of two-dimensional materials,the optical and electrical properties of heterojunctions,and the characterization of materials.The main work is as follows:(1)Mechanical stripping is adopted to overcome the van der Waals force between the layers of materials so that the bulk materials become layered two-dimensional materials,the thickness of the materials is determined,and different materials are stacked through the micro-platform to form heterogeneous nodes.(2)Electron beam exposure machine(EBL)is used to etch a channel on the silicon wafer for the convenience of making electrodes.The silicon wafer is placed on the evaporative coating machine and the metal electrode is evaporated and plated on the surface of the device.The formed device is characterized by Raman spectroscopy at room temperature for the heterogeneous junction,probe table electricity,and mapping table optical characterization.(3)electrical and optoelectrical measurements.study independently after material performance in a thin layer WSe2-ReSe2 heterojunction transistor as channel materials preparation,through the output characteristic curve and transfer characteristic curve of the electrical characteristics,determine the type of semiconductor,and calculating the carrier mobility,compared with that of current switch principal analysis.