A field effect transistor (FET) measurement of a SWNT shows a transition from a metallic one to a p-type semiconductor after helical wrapping of DNA. Water is found to be critical to activate this metal-semiconductor transition in the SWNT-ssDNA hybrid. Raman spectroscopy confirms the same change in electrical behavior. According to our ab initio calculations, a band gap can open up in a metallic SWNT with wrapped ssDNA in the presence of water molecules due to charge transfer.
@article{arxiv.1010.1616,
title = {Reversible Metal-Semiconductor Transition of ssDNA-Decorated Single-Walled Carbon Nanotubes},
author = {Misun Cha and Seungwon Jung and Moon-Hyun Cha and Gunn Kim and Jisoon Ihm and Junghoon Lee},
journal= {arXiv preprint arXiv:1010.1616},
year = {2015}
}