CVD growth of carbon nanotubes on catalyst patterns generated with AFM lithography

We obtain carbon nanotubes (CNTs) by chemical vapor deposition (CVD) using ethanol as carbon source. CNTs are grown on linear and rectangular patterns containing Co-Mo catalysts. These patterns were generated with a combination of dip-pen and 'scratching' lithography performed with Atomic Force Microscopy (AFM). In this procedure, a gold thin film deposited on porous alumina substrates is first scratched and subsequently a solution of Co and Mo acetates in ethanol is painted on the scratched area with a syringe mounted on the AFM instrument. CVD growth temperature of CNTs is of about 750°C with an ethanol exposure time of 30 min. In the linear patterns a dense film of CNTs is obtained with average lengths of 1 μm and in the rectangular patterns CNTs grow with diameters of about 50 nm. Sample analysis is performed with scanning electron microscopy (SEM) and AFM.