Determination of work function in the individual carbon nanotubes using electrostatic force microscopy

Abstract In this letter we report the determination of electron work function (WF) in the individual undoped, as-grown and thermally treated nitrogen-doped carbon nanotubes (CNTs) with the use of the electrostatic force microscopy (EFM). The determination of WF is based on the measurement of the contact potential difference between CNTs and the probe tip. Obtained mean values of WF for a large number of individual CNTs are in quantitative agreement with the value of WF obtained by X-ray photoelectron spectroscopy at the CNTs layers. The ability to determine WF in individual CNTs is due to the sensitivity of the EFM signal to the interaction of CNTs with the tip apex.