Internal stress induced metallization of single-walled carbon nanotubes in a nanotube/glassconducting composite

Abstract

Single-walled carbon nanotubes (SWCNTs) have been incorporated into a (Pb,Zn)—phosphate glass host by a melt-quenching technique. Studies of the optical and electronicproperties show that the nanotubes in the composite have suffered conformationaldeformations and attained a band structure of quasimetallic type, making the composite agood electrical conductor. Possible strains in the nanotubes of the composite such as radialcompression, torsion and bending have been considered and their role in modulating theband structures has been analyzed by judging the change in band gap energies (ΔE) of the deformed SWCNTs using an equation which is based on theπ-electron tight bindingmodel. The effect of σ*–π* hybridization due to the radial compression in generating the metallicity is also discussed.The carrier transport in the composite above room temperature has been shown to bedominated by fluctuation induced tunneling.