Study On Synthesis And Characterization Of Monolayer Molybdenum Disulfide By CVD Method

Monolayer molybdenum disulfide (MoS2) has recently attracted great interest due to its direct-gap property and potential applications in electronics, catalysis, photovoltaics and optoelectronics. However, the large-scale application of monolayer MoS2 is dependent on the controllable preparation with large area and high quality.This thesis mainly focuses on the controllable preparation of large-grain MoS2 and large-area monolayer MoS2 films by CVD method.We introduced the basic structure and properties of MoS2 in detail.We reviewed common synthesis methods of monolayer MoS2, and summarized the applications of monolayer MoS2 in the areas of solid lubricant, field effect transistor, sensor and catalyst. Meanwhile, we systematically introduced several characterization methods of monolayer MoS2,including optical microscope, scanning electron microscope, Raman spectroscopy and photoluminescence (PL) spectroscopy.We studied the APCVD method for the preparation of monolayer MoS2 by MoO3 sulfurization. We studied the influence of growth conditions on the growth of monolayer MoS2, such as substrates’ cleaning, growth temperature, the concentration of M0O3 and so on Optical microscope, scanning electron microscopy and Raman spectra revealed that the sample is a uniform monolayer MoS2 up to 50μm in size.We synthesized graphene quantum dots (GQDs). Utilizing GQDs as seeding promoters, a large-area and uniform MoS2 monolayer was achieved by APCVD method with lateral size of at least 500 μm, which was confirmed by optical microscope, scanning electron microscopy, Raman and PL spectra.