Synthesize And Electrical Properties Of Monolayer And Fewer Layers Disulfide

Since the discovery of graphene in 2004,two-dimensional materials have become hotspot-s in basic science and advanced technology research due to their excellent properties.Al-though graphene has excellent optical,electrical,and mechanical properties,its zero-energy band gap（semi-metallic）properties prevent it from being directly used in semiconductor electronic and optoelectronic devices.The transition metal chalcogenide is a semiconductor material with a structure similar to graphite,and also has good stretchability and flexibility.Therefore,the transition metal chalcogenide has aroused great interest.This article mainly uses chemical vapor deposition to prepare（single layer and few layers）controllable tungsten disulfide,and studies its physical properties and photoelectric properties.（1）Through the control variable method,the factors influencing the deposition of tung-sten disulfide such as deposition temperature,carrier gas flow rate,deposition time and sub-strate position were studied in detail,and the controllable preparation of single layer and few layers of tungsten disulfide was realized.The Raman and photoluminescence spectra of single-layer and few-layer tungsten disulfide were studied.And conducted Raman spec-trum test and photoluminescence spectrum test in the temperature range of 80-300 K.The study found that the Raman spectrum of single-layer and few-layer tungsten disulfide in-creased with temperature,the peak positions of the two vibration modes E₂₂)and A₁₂)were blue-shifted,and the peak position of the single-layer tungsten disulfide photoluminescence occurred red-shifted The peak positions of the two sub-peaks of layer tungsten disulfide A and B are red-shifted.（2）Tungsten disulfide with different number of layers is made into photoelectric de-vice,and its photoelectric performance is tested.It was found that as the number of layers increased,the resistance of tungsten disulfide decreased significantly.The mobility is obvi-ously increased,which is caused by the decrease of the interfacial charge scattering of tung-sten disulfide with the increase of thickness.Single-layer and few-layer tungsten disulfide devices were irradiated with lasers of different wavelengths and different power densities.It was found that with the increase of the number of layers,the response rate of tungsten disul-fide increased significantly.When the incident power density is 0.13 m W/cm²,the response rate of the 4-layer tungsten disulfide to 457 nm laser reaches 16.58 k A/W,which shows very excellent photoelectric performance.