| Compared with the traditional bulk materials, low-dimensional nanomaterials and nanostructures exhibit unique electronic, optical, magnetic and other physical properties, and have important application value. Recent studies have shown that two dimensional materials, represented by graphene, have exhibited good social value and economic value in many fields such as semiconductors, electronic devices, energy storage and conversion. Meanwhile, great efforts are need to be made to achieve the goal of industrial scale applications. And the synthesis of materials is the base. Take graphene for example, high temperature is necessary in most of preparation processes.While high temperature will hinder the combination of graphene and semiconductor industry. So the development of growth of graphene at low temperature has great significance. In addition, layered hexagonal boron nitride and semiconducting two dimensional materials make excellent additions to semi-metallic graphene.Preliminary studies have shown that the former can significantly improve electronic performance of devices made of graphene and other materials, while the latter have great potential applications in many aspects such as photodetectors, solar cells,display and other areas. However, controlled synthesis of these two kinds of materials is not easy to realize and in most cases, the synthesis process is full of randomness.The uncertainty hinder further applications of two dimensional heterostructures and other nanocomposite structures. For the synthesis of two-dimensional materials,semi-metallic graphene, insulating hexagonal boron nitride and semiconducting tungsten disulfide were selected for study. Through chemical vapor deposition,controlled synthesis, structure characterization, physical property measurement and preliminary application were explored. And the results will be a useful reference for the effective synthesis and scale applications of low-dimensional nanomaterials. The main content of this paper include the following three aspects.1. High quality layered ternary topological insulator Bi2Se3XTe3(1-x) was synthesized on the fluorophlogopite mica and SiO2/Si and other substrates by chemical vapor deposition. The modulation of microstructures of Bi2Se3xTe3(1-x) was realized by adjusting concentration of selenium doping. Raman was use to characterize the products. It was found that with the increase of Se doping level,Raman peaks of the nanosheets moves to high frequency and discontinuous variation of the Raman peak was observed. These results have reference value for the synthesis of high quality topological insulators and the study of its physical properties and applications.2.The ultra-thin large-area carbon film was synthesized by atmospheric-pressure low-temperature chemical vapor deposition. Carbon film with thickness of 2-5nm can be synthesized on copper foil and glass substrate covered with 100nm copper by adjusting experimental parameters even when the temperature is as low as 500 ?. The transmission of the synthesized carbon film in 400-700nm is more than 90% and a good sheet resistance was achieved. This method provides a new way to directly grow ultra-thin carbon film on semiconductor substrate at low temperature.3. High quality layered semiconducting tungsten disulfide was synthesized on Si02/Si by chemical vapor deposition. A two-terminal device was fabricated through micro-nano fabrication. The results showed that the device has a good response to water vapor. The current increased obviously with the concentration of water vapor. A humidity sensor was realized. This study is useful for the device application of two-dimensional layered semiconducting materials. |
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