Nonmetallic Conduction Property of a DNA Templated Gold Nanowire

Nanowires based on DNA are exciting materials with several possible applications in nanoelectronics because of the self-assemble capability for the designed nanostructure. In this study, we have carried out electrical and thermal conduction measurements on a metallized single DNA molecule. The measured values of the electrical and thermal conductivity were about 1.42 × 10¹ S/cm and 149.8 W/mK at room temperature, respectively. The measured value of the Lorentz number was about 3.6 × 10⁻⁴, which is incompatible with that predicted by the Wiedemann-Franz law. The temperature dependent electrical conductivity shows that electron transport in metallized DNA occurs by the hopping process similar to that in nonmetallized DNA. Atomic force microscopy reveals nanoscale discontinuities in the gold layer around the DNA. While the gold layer assists the DNA in electron conduction, the overall conduction of the metallized DNA is dominated by the DNA rather than the coating. These results suggest that the DNA is potentially a better thermal conductor than the metal coating and that its effective conductivity may be large. This interesting physical property may make the DNA useful for bioapplications involving significant heat transfer.