气体配比对硼掺杂碳纳米管生长特性的影响

Effects of gas composition on the synthesis of boron-doped carbon nanotubes

采用电子回旋共振微波等离子体化学气相沉积技术(ECR-CVD),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、结构及组分进行表征。结果表明:B2H6对纳米管的生长具有较大影响。气源中含有少量的B2H6就会破坏纳米管的定向生长,使纳米管变得弯曲;随着气源中B2H6比例的增加,纳米管结构从中空结构转变为类竹节结构,多壁管外径由60nm^90nm增大至200nm^250nm,管壁由10nm^20nm增厚至70nm^100nm,表面变得粗糙,同时纳米管的生长速度降低;纳米管中的B/C原子比随着B2H6比例的增大而增大,当B2H6/CH4体积配比为2∶1时B/C原子比增至28∶72。

Boron-doped carbon nanotubes （CNTs） were synthesized on porous silicon by electron cyclotron resonance chemical vapor deposition from CH4 ,B2H6 and H2 were used as the source gases and Fe3O4 nanoparticles as the catalyst. The effects of gas composition on the growth characteristics of boron-doped CNTs were investigated. Scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy were used to evaluate the structure and composition. Results show that addition of B2H6 influences the growth characteristic of CNTs greatly, making CNTs bend. Increasing the amount of B2H6 leads to a structural change in the CNTs from straight tubular to bamboo-like. Outer diameter increases from 60 - 90 nm to 200 - 250 nm, tube wall thickness increases from 10 - 20 nm to 70 - 100 nm, and a rougher surface and a decreased growth rate is noted. An increase in the B/C ratio of the specimen was detected as the amount of B2H6 increased. The B/C ratio can be up to 28：72 when the B2H6/CH4 ratio is 2： 1.