【作者】 王志；

【导师】 巴德纯；

【作者基本信息】 东北大学 ， 流体机械及工程， 2004， 博士

【摘要】 本文采用电子回旋共振微波等离子体化学气相沉积方法(ECR-CVD),以CH4和H2为气源、Fe3O4纳米粒子为催化剂,未加电场情况下,在多孔硅基底上制备出大面积阵列碳纳米管。使用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、X射线能量色散分析(EDX)、拉曼光谱(Raman)对样品形貌和结构进行了表征,结果显示:合成的碳纳米管为多壁碳管;碳纳米管直径60～90 nm,长度约8μm;碳纳米管的生长采取催化剂底端生长模式。并对其定向机制进行了探讨。通过改变实验参数,研究了气氛组成、气压、温度和反应时间对碳纳米管生长的影响。结果表明:气氛组成、气压和温度综合影响碳纳米管的形貌、生长速度和取向性,碳纳米管在一定时间后停止生长。本实验系统在CH4浓度50%、气压30Pa、温度650℃工况下实现了碳纳米管的最优定向生长。研究了不同催化剂的催化效果和不同基片对碳纳米管生长方式和形貌的影响。分别以Fe3O4、Co纳米粒子及Fe(NO)3溶胶为催化剂在多孔硅基底上制备了碳纳米管;在多孔硅、Si(111)面和石英基底上以Fe3O4纳米粒子为催化剂实现了碳纳米管的生长。通过对样品的形貌、尺寸及结构的表征,讨论了催化剂和基底对碳纳米管形貌、密度和取向性的影响。结果表明:催化剂影响碳纳米管的成核密度和生长速度,基底通过影响催化剂的特性和分布均匀性,对碳纳米管的形貌和生长模式产生重要影响。使用原子力显微镜(AFM)对碳纳米管的形貌进行了观测研究。利用ECR-CVD技术,以Fe3O4纳米粒子为催化剂,CH4、B2H6和H2为气源,在多孔硅基底上制备出了掺硼碳纳米管。研究了不同B2H6/CH4气体配比对碳纳米管生长特性的影响。使用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线光电子谱(XPS)对样品的形貌、结构及组份进行表征。结果表明: B2H6的通入对纳米管的更多还原

【Abstract】 The large area well-aligned carbon nanotube (CNT) arrays were synthesized on porous silicon by electron cyclotron resonance chemical vapor deposition (ECR-CVD) with CH4 and H2 as the source gases, Fe3O4 nanoparticle as the catalyst and without applying electrical field. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD) and energy dispersive X-ray analysis (EDX) were used to evaluate the structure and composition. The result showed the CNTs have outer diameters of about 60～90 nm and length of 8μm and showed straight tubular and chain structures.The effects of process parameters such as gas composition, working pressure, temperature and deposition time for CNTs growing characteristics were investigated. The result shows that the gas composition and working pressure influence the concentration of carbon radical in the chamber, which may influence growth rate, density and aligned growth of CNTs; The temperature controls the diameters of CNTs by changing the size of catalyst but CNTs can’t tend to aligned growth at lower temperature; First, CNTs become longer and longer according to the deposition time, but they stop growing after a certain time.The influence of different catalyst and substrate were studied. Fe3O4 nanoparticle, Co nanoparticle and Fe(NO)3 sol were used as catalyst and porous silicon, Si (111) and quartz were used as substrates, respectively. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) were used to evaluate the morphology and structure. The results show that the catalyst affects the density and growth rate, the substrate affects the morphology and growth mode by controlling the characteristic and distributing uniformity of catalyst. Well-aligned carbon nanotubes were synthesized on porous silicon with Fe3O4 nanoparticle as catalyst in the present study.Boron-doped carbon nanotubes (CNTs) have been synthesized on porous silicon by ECR-CVD. CH4、B2H6 and H2 were used as the source gases and Fe3O4 nanoparticle as the catalyst. The effects of gas composition for boron-doped CNTs growing characteristics were更多还原