衬底温度对碳纳米管生长和结构的影响

Influence of Substrate Temperature on Growth and Structures of Carbon Nanotubes

用CH4、NH3和H2为反应气体,利用等离子体增强热丝化学气相沉积在沉积有Ta缓冲层和Ni催化剂层的Si衬底上制备了准直碳纳米管,并用扫描电子显微镜和透射电子显微镜研究了它们的生长和结构随温度的变化。结果表明生长的准直碳纳米管是竹节型结构,其直径随衬底温度的降低而减小,生长速率随衬底温度的升高有一极值。从催化剂在衬底温度作用下的变化开始,分析了衬底温度对碳纳米管生长和结构的影响。

Aligned carbon nanotubes （ACNTs） are synthesized on silicon substrate coated with Ta buffer layer and Ni catalyst film by plasma-enhanced hot filament chemical vapor deposition using CH4, NH3, and Hz as the reaction gases, and the change of their growth and structures with the substrate temperature are investigated by scanning electron microscopy and transmission electron microscopy. The results indicate that the ACNTs are the bamboo structure and their diameters are reduced with reduction of the substrate temperature. Simultaneously, their growth rate shows a maximum value with increasing of the substrate temperature. From the change of the catalyst under the action of the substrate temperature, the effects of the substrate temperature on the growth rate and structures of the ACNTs are analyzed.