Patterning of Catalysts for the Selective Growth of Carbon Nanotubes Using Laser Irradiation of Nickel Nitrate

We developed a simple method to produce patterned catalysts for the growth of carbon nanotubes (CNTs) on Si substrate using laser irradiation of Ni nitrate. We found that Ni nitrate can easily be decomposed into Ni oxide by KrF laser irradiation and that unexposed Ni nitrate can be removed using deionized (DI) water. Once we obtained patterned Ni oxide, we were able to synthesize multi-walled CNTs using a conventional thermal CVD. This new method does not require any photoresist or vacuum processes. Not only is the method compatible with low-temperature and large-area fabrication, it also significantly reduces the total processing steps required for conventional lithographic patterning technology. A detailed investigation of the decomposition process of this patterned catalyst and the microstructure of the patterned multi-walled CNTs was carried out using IR, SEM and TEM.