Morphology-controlled Synthesis Of MoS₂ Nanostructures And Related Properties

Because of the special structure and photoelectric properties, graphene-like Mo S2 has broad application prospect in many fields such as solar battery, field effect transistor, sensor,energy storage and so on. Due to the anisotropy of its structure, the effects of different topography on the property is very significant. Therefore, it is necessary to improve existing methods and technology, while continue to develop methods and new technology. And it is also very important and significant to further expand the nanostructure disulfide preparation and precise control of Mo S2 by changing the chemical environment of the preparation. So that it can be significantly improved the potential application performance and applied in more areas. The current thesis is focused on prepare Mo S2 in different environments, to study the formation mechanism and observe the optical properties by discussing the topography of the resulting product.1. The MoS2 flakes are directly prepared on SiO2/Si substrates with chemical vapor deposition(CVD) in varied carried gas flow rate. It can be found that the monolayer and dendritic morphologies Mo S2 flakes can be formed with different Ar flow rate, respectively. It demonstrates that the carrier gas flow rate has strong influence on the structure and morphology of CVD-grown Mo S2 flakes, and consequently tailors the optical properties of MoS2 flakes significantly.2. The precise control of the morphology of monolayer MoS2 is of particular importance for their potential applications and device performance. In this work, we present an experimental method to study the shape evolution of the chemical vapor deposition(CVD) grown Mo S2 flakes. We observed that the morphology of monolayer Mo S2 flakes transformed from truncated triangular shape to triangular shape by increasing the stoichiometric ratio of S:Mo, and consequently tailor the optical properties of Mo S2 flakes.3. The precise control of the morphology and crystal shape of Mo S2 nanostructures is of particular importance for their application in nanoelectronic and optoelectronic devices. Here,we describe a single step route for the synthesis of monolayer-by-monolayer stacked pyramid-like Mo S2 nanodots on monolayered Mo S2 flakes using a chemical vapor deposition method. First-principles calculations demonstrated that the bandgap of the pyramid-like Mo S2 nanodot is a direct bandgap.Enhanced local photoluminescence emission was observed in the pyramid-like Mo S2 nanodot, in comparison with monolayered Mo S2 flakes. The findings presented here provide new opportunities to tailor the physical properties of Mo S2 via morphologycontrolled synthesis.