Charge transport and photoresponses in a single-stranded DNA/single-walled carbon nanotube composite film

Abstract

Electrical conductivity and photoresponse measurements have been carried out on a single-stranded DNA (ssDNA)/single-walled carbon nanotube (SWNT) composite film in comparison to those of a SWNT film. While the temperature-dependent electrical conductivity of the pristine SWNT film was described well by the combined mechanism of a three-dimensional variable-range hopping and hopping conduction, that of the ssDNA/SWNT composite film followed a fluctuation-induced tunneling model. Besides, competition of photoexcited charge carrier generation and oxygen adsorption/photodesorption in the photoresponses of the films was observed and discussed in view of the role of the DNA wrapping. Thus, the biopolymer coating of the SWNTs is shown to play a significant role in modifying the charge dynamics of the composite system. (C) 2013 AIP Publishing LLC.