Preparation Of C-Si Composite Nanotubes

Carbon nanotubes (CNTs) possess unique one dimensional structure, and thus exhibit many excellent physical and chemical properties. However, the CNTs are generally metallic. Although the single wall CNTs with some structure are semiconducting, the controlled synthesis of the structure is difficult in practice. By using the CNTs as templates and solid reaction, various composite structures with new properties can be obtained, which is important both for scientific research and technological application. This work trys to synthesize semiconducting SiC nanotubes or Si/C composite nanostructures. The main contents include:Firstly, The effects of temperature and pressure on the preparation of the Si-C composite were determined. It is indicated that the SiC concentration increases with increasing the evaporation temperature and decreasing the ambient pressure.The formation of SiC started from 1200°C and was obvious at 1300°C and above.Secondly, The concentration of the C dominates in the obtained Si-C composite materials, which shows that the products may be the cable structure of SiC/C with semiconducting SiC as the outer layer.Thirdly, The dramatic morphology changes were observed after solid reaction. The CNTs were curly, entangled, and with rough surface, but the converted Si-C composite materials are straight and with smooth surface.Fourthly, The products were characterized by catholuminescence spectroscopy. The emission peaks at 450 nm and 580 nm were observed. Interestingly, the emission image from single nanotubes was observed, which demonstrated the formation of the semiconducting SiC layers.