Direct Fabrication of Carbon Nanotubes STM Tips by Liquid Catalyst-Assisted Microwave Plasma-Enhanced Chemical Vapor Deposition

摘要

Direct and facile method to make carbon nanotube (CNT) tips for scanning tunneling microscopy (STM) is presented. Cobalt (Co) particles, as catalysts, are electrochemically deposited on the apex of tungsten (W) STM tip for CNT growth. It is found that the quantity of Co particles is well controlled by applied DC voltage, concentration of catalyst solution, and deposition time. Using optimum growth condition, CNTs are successfully synthesized on the tip apex by catalyst-assisted microwave-enhanced chemical vapor deposition (CA-MPECVD). A HOPG surface is clearly observed at an atomic scale using the present CNT-STM tip.