Kelvin Probe Force Microscopy Imaging Using Carbon Nanotube Probe

We have measured the potential profiles of the contact potential difference (CPD) between Al-evaporated substrates and dispersed carbon nanotubes (CNTs) by Kelvin probe force microscopy (KFM) using both a conventional Au-coated Si (Au–Si) probe and a CNT probe. The lateral resolutions of both topography and the potential distribution image were improved by using the CNT probe. The CPD has been measured for CNTs with various diameters. We observed that the CPD increases with an increase in the diameter. This indicates that the work function of CNTs increases with an increase in the diameter.