Research On Preparation And Photoelectric Properties Of MoS₂ Films

Molybdenum disulfide is a typical n-type semiconductor.Compared with zero-bandgap graphene,it has tunable bandgap of 1.2 eV¹.8 eV,so it has advantages in building electronic devices?such as field-effect transistors,photoelectric devices?.Moreover,compared with silicon with three-dimensional structure,molybdenum disulfide with two-dimensional structure has a broader prospect in such fields as smaller-size,higher-efficiency electronic chips and nanoelectronic devices due to its single layer thickness of 0.65 nm and special optical,electrical and mechanical properties.In addition,Mo and S are natural minerals with abundant reserves and low price,which enhances the possibility of MoS₂ application in the field of photoelectric devices.A few decades ago,the study of molybdenum disulfide was limited to lubricants.In recent years,with the development of molybdenum disulfide,more attention has been paid to its applications in nanoelectronics,solar cells,flexible and transparent materials,etc.Therefore,this topic was determined to study the preparation of MoS₂ thin film and its photoelectric device.The main research contents are as follows.Firstly,the process parameters of RF magnetron sputtering for MoS₂ thin film were studied in this paper:four groups of thin film samples were prepared by RF magnetron sputtering on quartz substrate and changing sputtering pressure,sputtering power,sputtering time and annealing temperature by controlling a single variable.By X-ray diffraction?XRD?,atomic force microscope?AFM?,scanning electron microscope?SEM?,UV-VIS spectrometer,photoluminescence spectrometer,and Raman spectrometer,the thin film were characterized.After analysis and comparison of the quality of thin film crystal,the surface morphology,and optical performance respectively,the best process parameters for the preparation of film were obtained,1.0 Pa and 200 W.Secondly,the photoelectric properties of MoS₂ thin films are changed due to the great influence of sputtering time and annealing temperature on the surface morphology of MoS₂ thin films.In this paper,the photoconductive detector was prepared and the photoelectric response of the film samples were tested.According to the spectral response and I-V characteristics,the influence of the film morphology and crystal quality on the photoelectric performance of the film was obtained,and the optimal sputtering time was40 min and the annealing temperature was 400°C.In addition,the influence of Ag particles on the photoelectric properties of MoS₂ thin film was studied by doping Ag particles on the surface of MoS₂ thin film based on local surface plasmon resonance effect.Based on the above,MoS₂/MgZnO:Ga heterostructure photodetector was further prepared,and the influence of MgZnO:Ga layer thickness on the device was studied.Furthermore,based on the knowledge of molybdenum disulfide materials,heterojunction device based on single layer molybdenum disulfide was designed and the test of its detection performance are attempted.The device structure is n-MoS₂/p-GaN,which can realize dual-band detection.Under the bias voltage of 1 V,the responsivity reached 431.1 mA/W and 530.7 mA/W,respectively,being illuminated at 325 nm and845 nm.