辅助气体对RF-PECVD制备碳纳米管薄膜形貌的影响

采用射频等离子体增强化学气相沉积(RF-PECVD)技术,以Ni为催化剂,经600℃裂解C2H2在Si基底上制备出定向碳纳米管薄膜。采用扫描电子显微镜(SEM)表征了刻蚀后Ni颗粒与沉积的碳纳米管薄膜的形貌。研究了辅助气体对等离子体预处理催化剂与碳纳米管生长的影响。结果表明:辅助气体(H2与N2)流量比对催化剂颗粒尺寸、分布以及碳纳米管生长有显著影响;合适的气体流量比有利于减少碳纳米管薄膜的杂质颗粒,促进其定向生长。预处理过程中气体流量比H2:N2=20:5时,预处理后催化剂Ni颗粒分布密度大、粒径小且分布范围窄,适合碳纳米管均匀着床;沉积生长碳纳米管薄膜时,H2:N2=20:15可得到纯度高、定向性好的碳纳米管。

Effect of Auxiliary Gases on Morphology of Carbon Nanotubes Film Synthesized by RF-PECVD

Oriented carbon nanotubes film was synthesized on Si substrates by radio-frequency plasma enhanced chemical vapor deposition via decomposing acetylene at low temperature with Ni as catalyst.The distribution of Ni particles and morphology of carbon nanotubes film were characterized by using scanning electron microscope.The effect of auxiliary gases on catalyst pretreatment and growth process of carbon nanotubes were discussed.The results showed that the grain size and distribution density of catalyst particles etched by different flow ratio of gases(hydrogen and nitrogen) had strong effect on the morphology of carbon nanotubes.A proper flow ratio of hydrogen and nitrogen tended to produce the defect-free carbon nanotubes and to improve the growth of oriented films.When the ratio of hydrogen and nitrogen was 20:5,the size of Ni particles was small,the density high and the size distribution range narrow.Furthermore,when the ratio was 20:15,the carbon nanotubes film with high purity can be obtained.