Effect of hydrogen plasma pretreatment on growth of carbon nanotubes by MPECVD

We have grown carbon nanotubes (CNTs) with a microwave (μW) plasma enhanced chemical vapor deposition (MPECVD) method, which has been regarded as one of the most promising candidates for the synthesis of CNTs due to the vertical alignment, the low temperature and the large area growth. We use methane (CH4) and hydrogen (H2) gas for the growth of CNTs. Ni catalytic layer (10 nm thick) were deposited on the Ti-coated Si substrate by RF magnetron sputtering method. In this work, we report the effects of pretreatment μW power on the growth of CNTs. We have pretreated the Ni catalytic layer in different μW power (600, 700, and 800 W) and grown same μW power (800 W). Scanning electron microscopy (SEM) images show Ni catalytic layer diameter and density are varied dependent with their pretreatment conditions. Raman spectroscopy of CNTs shows that ID/IG ratios and G-peak positions vary with pretreatment conditions.