Preparation And Characterization Of Nano-Molybdenum Disulfide And Its Electrical Properties

Molybdenum disulfide（MoS₂）is a typical member of layered transition metal sulfides,which has been widely applied in the field of lubricants and catalysts due to its special crystal structure and excellent physical chemistry properties.Recently,molybdenum disulfide has attracted more attention in view of good prospects in the field of lithium-ion batteries,hydrogen storage materials,optoelectronics devices and biomedicine because of its excellent chemical stability,mechanical flexibility and optical and electrical properties.In this paper,the MoS₂ microspheres were successfully prepared via a facile hydrothermal route,and the as-prepared samples were characterized by X-ray powder diffraction（XRD）,spectroscopy（EDS）,scanning electron microscopy（SEM）and transmission electron microscopy（TEM）.Meanwhile,the impact of the added amount of oxalic acid,the kinds of raw materials,the atom ratio,reaction temperature and reaction time in the procedure of synthesis were also studied detail.The optimum condition of obtaining the MoS₂ microspheres was determined to use sodium molybdate as the molybdenum source with additional 50%mol of oxalic acid,the ratio of Mo and S was obtained to be more than 4:1,the synthesis temperature and time was demonstrated to be 210 ^oC and 20 h,respectively.The dispersion of molybdenum disulfide samples could be improved obviously after adding different dispersants.In additional,the MoS₂ microspheres with flower-shape grow more independent with adding the different dispersants.It is noteworthy that the sheet structure was found in the CPB-adding sample.The SEAD results indicated many diffraction spots in circles,indicating that the MoS₂microspheres exhibits a highly crystalline nature with corresponding（002）reflections,can be indexed to the structure of MoS₂.Meanwhile,the I-V performance of the pure MoS₂ and different dispersants adding samples were tested and studied.The experimental condition was determined to analysis under a certain bias voltage,the results showed that I-V properties of PEG,PVA and PVP adding samples exhibited an obvious semiconducting materials properties.On the contrary,the I-V curve of PVP-adding sample is a little smooth so that this material can obtain stable current with same voltage to be regarded as a conductive material.A large area of two-dimensional layered MoS₂ film was successfully synthesized via the chemical vapor deposition method.And the samples were characterized by scanning electron microscopy（SEM）,Raman spectroscopy（Raman）and atomic force microscopy（AFM）.The results showed that the maximum diameter of the as-prepared molybdenum disulfide film is 80μm,and the layer thickness is 0.66 nm.