Optical characterization of DNA-wrapped carbon nanotube hybrids

Optical characterization of DNA-wrapped CoMoCAT carbon nanotube hybrids (DNA-CNT) and semiconductor-enriched DNA-CNT was carried out using resonant Raman spectroscopy (RRS) and photoluminescence (PL) experiments. The values of radial breathing modes frequency omega(RBM) were found to be relatively insensitive to the type of wrapping agents surrounding the nanotube. The values of omega(RBM) and the first and second resonant interband transitions, E-11 and E-22, for a particular (n, m) tube for all sample types in RRS and PL measurements are found to correspond to the values obtained for SDS-dispersed nanotubes measured with PL, but with a shift in E-ii ranging from 10 to 80 meV. The DNA-wrapping has shown not only to provide good isolation to the individual nanotube in a bundle, but the DNA wrapping mechanism for the CoMoCAT sample has also been shown to be diameter selective. (C) 2004 Elsevier B.V. All rights reserved.