Preparation And Photoelectric Properties Of Novel Two-dimensional Material Field Effect Transistors

New two-dimensional layered semiconductor materials such as transition metal chalcogenide compounds(TMDC)and graphene structure compounds have unique energy band structures and crystal structures.They have become the current international research frontiers and hot spots in materials,physics and other disciplines.Catalysis and other fields are widely used.However,the surface effects generated during the fabrication of single-layer two-dimensional nanomaterial devices,such as the influence of impurities such as photoresist residues and physically adsorbed water and oxygen molecules on the surface,significantly reduce their performance.Appropriate methods for removing physically adsorbed contaminants are essential for achieving high-performance TMDC devices.In this paper,the regulatory factors related to impurities in single layer tungsten diselenide(WSe₂)and single layer molybdenum disulfide(Mo S₂)based field effect transistor(FET)in TMDC are studied;in addition,high quality germanium hydride(GeH)and its The controllable preparation process of the field effect transistor was studied,and its photoelectric response characteristics were studied.The main research contents and results are as follows:(1)Single-layer WSe₂ and single-layer Mo S₂were prepared by the traditional mechanical stripping method,and single-channel WSe₂ and multi-channel Mo S₂FET devices were prepared by micro-nano processing technology to realize the gate voltage regulation of the Fermi surface of TMDC And,through the device under different conditions(high vacuum,340 K in-situ annealing,laser irradiation)transfer characteristic curve to study its electrical properties.The results show that for TMDC materials,laser irradiation under high vacuum greatly improves the on-state current,switching ratio and electron mobility,and significantly reduces the sub-wide swing,device channel resistance and contact resistance.This article believes that laser irradiation can remove impurities adsorbed on the device,thereby improving its electrical performance.(2)Based on the study of the electrical properties of TMDC,a 532 nm laser is used to study the regulation effect of laser irradiation on the performance of FET devices.The results show that within a certain range,as the laser power increases,the conductivity of the device increases;with fixed irradiation power,the photocurrent will increase to saturation with the irradiation time;the time-dependent response characteristic curves under different processing conditions show WSe₂ field effect transistors It has very good switching performance and excellent photoelectric conversion performance;the photocurrent of the device after laser irradiation is 10 times that of the original,which proves that laser irradiation improves the contact resistance,there by increasing the efficiency of photoexcited carrier injection into the electrode,resulting in The photocurrent increases.(3)High-purity two-dimensional Ge layered compound GeH was prepared by melting method and chemical de-intercalation method,and the electrical performance control methods of GeH bulk materials and nano-films were studied respectively.For GeH bulk materials,electrical measurements under a high-vacuum probe table show that annealing is an effective means to improve its electrical properties.This article believes that this is due to dehydrogenation;for GeH nano-films,a smoother surface was prepared by mechanical peeling Nano-thin GeH sample(8.3 nm),successfully prepared the corresponding FET device,and realized the gate voltage regulation of GeH nano-thin layer device.