Single-walled carbon nanotubes as a dopant p-type cuprous oxide films

Abstract

p-type cuprous oxide (Cu(2)O) films doped with single-walled carbon nanotubes (SWCNTs) were synthesized using the two-step process of electrochemical co-deposition and subsequent thermal oxidation. SWCNTs are known to act as a conducting pathway in various SWCNT-based composite materials because of their low electrical resistivity in the longitudinal direction. However, they act as an electron acceptor dopant rather than a carrier pathway in p-type Cu(2)O. Results show that the doping of SWCNTs in Cu(2)O films increases the hole concentration and decreases the carrier mobility with increasing dopant concentration. As a result, the electrical resistivity decreased from 290 to 0.8 Omega cm as the amount of dopant increased. The electronic energy band structure, as determined by X-ray and ultraviolet photoelectron spectroscopy, revealed that the doping of SWCNTs moved the Fermi levels of Cu(2)O films toward the valence band maximum by 0.24 eV. This confirms that the SWCNTs act as an electron acceptor and increase the hole concentration and electrical conductivity of the Cu(2)O films, despite the lower mobility. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.