Conductivity Change of Carbon Nanotube with Strong Electrom-donating and withdrawing Molecules

Abstract

Electron transport properties of single-walled carbon nanotubes (SWNTs) are investigated with TTF and TCNQ molecules, i.e. tetrathiafulvalene and 7,7,8,8-tetracyano-p-quinodimethane. TTF and TCNQ are well known strong charge transfer molecules, i.e. TCNQ is an avid acceptor of electrons and TTF is an electron donor. From the I-V measurement, current is found to decrease and increase distinctly upon the adsorption of TTF and TCNQ, respectively. From the analysis of X-ray photoelectron spectroscopy (XPS) data, the 2Pz orbitals of SWNT are strongly coupled with the pi-orbitals of both TTF and TCNQ molecules. The results above can be directly used to control electron concentration within p-type or n-type carbon nanotubes to form nano electronic devices.