Research On Design And Performance Of Two-dimensional Tungsten Disulfide Van Der Waals Heterojunction Broadband Photodetector

High-performance wide-band photodetectors have caused extensive scientific research due to their important application value in the field of optoelectronics.In recent years,two-dimensional?2D?materials have been widely used in the field of photoelectric detection due to their unique photoelectric characteristics.Among the many two-dimensional material systems,transition metal chalcogenides?TMDs?have become highly competitive in the field of optoelectronic devices due to their wide adjustable band gap range,high carrier mobility,excellent air stability and mechanical flexibility Two-dimensional material.Tungsten disulfide?WS₂?,as a typical member of TMDs,is one of the ideal materials for constructing high-performance photodetectors.Although great achievements have been made in photodetectors based on two-dimensional materials,the current two-dimensional materials have the disadvantages of weaker light absorption,smaller sample size,and larger exciton effect,which limit their high further applications in performance photoelectric detection.This paper uses thermal decomposition to synthesize a large area of two dimensional WS₂ thin film,and design and construct a two-dimensional/three-dimensional?2D/3D?mixed-dimensional van der Waals heterojunction device to achieve high-performance photoelectric detection.The main research contents are as follows:Large area 2D WS₂ thin film materials were synthesized by thermal decomposition method,and through high-resolution transmission electron microscopy?HRTEM?,X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,atomic force microscope?AFM?And Raman spectroscopy?Raman?and other characterization methods to characterize the morphology,structure and composition of the synthesized WS₂ thin film material.A WS₂/Si mixed-dimensional van der Waals heterojunction photodetector with a type-? energy band arrangement structure was prepared in situ.This heterojunction device produces a current switching ratio of more than 10⁶ under zero bias and 980nm light,a responsiveness of 224 m A/W,a specific detection rate of up to 1.5×10¹²Jones,a response speed of 16.2/29.4?s at a 3d B bandwidth,and a response to 3043nm.The mid-infrared signal has good optical response.In addition,we also constructed and tested 4×4 array devices,which proved that the constructed heterojunction devices have high stability and repeatability.These results show that the WS₂/Si type-? heterojunction has great application potential in wide-band photoelectric detection and integrated photovoltaic systems.The WS₂/Ge mixed dimension van der Waals heterojunction photodetector was designed and constructed.The heterojunction device has a maximum response of 139m A/W to a 1550 nm infrared signal under zero bias,a specific detection rate of 2.45×10¹⁰ Jones,a response speed of 11.5/81.3?s at a 3d B bandwidth,and detection wavelength coverage from ultraviolet?265 nm?to near infrared?1550 nm?.In addition,based on the good infrared detection capability of the heterojunction device,we also explored the infrared imaging performance of the device.The results show that the WS₂/Ge van der Waals heterojunction photodetector has important application value in the broad-band photoelectric detection and infrared imaging.