Carbon nanotubes grown from nickel catalyst pretreated with H2/N2 plasma

To find the possibility of using a low-temperature process in growing carbon nanotubes (CNTs), nickel catalyst converted from film into particles by microwave H2/N2 plasma and the following CNT growth are all kept at a low temperature of 250 °C. The flat panel display industry requests low-temperature rather than the traditional high-temperature process for CNT growth. It was found that H2/N2 proportion is very sensitive to nickel morphology and the subsequent CNT growth. Better nickel and CNTs morphology are obtained for the proportion H2/N2=3/1 than those for the generally used pure hydrogen environment. The process pressure selection during pretreatment can determine whether CNTs are grown or not. The diameter of growing CNTs is proportional to nickel particle size. Field emission results support field amplification coefficient claim. The long tube length and high tube density of growing CNTs demonstrate low threshold electric field. This work shows the potential to use H2/N2 instead of pure hydrogen plasma in growing qualified CNTs applied in display industry.