Electrical conductivity of lambda DNA-Pd wire

Abstract

Recently DNA molecules have been focused on as electronic elements in the field of nanometer-scale electronics. One of the fundamental issues in this research area is the development of methods to measure accurately an electrical conductivity of DNA wire. The DNA tweezers we have recently developed have a great advantage of measuring the electrical current passing through DNA wire. In this paper, we investigated the electric conduction of lambda DNA molecules covered with Pd colloids using micromachined DNA tweezers that has a pair of opposing probes for retrieving DNA molecules. The molecules were retrieved from a solution containing lambda DNA by applying RF power between the probes in the solution. The retrieved molecules were then soaked in a colloidal solution containing cationic Pd particles, which results in a DNA-Pd wire bridged between the tweezer probes. Current-voltage curves for the DNA-Pd wire can be measured between the DNA tweezers probes, and the resistivity of the DNA-Pd wire was approximately 74 Ωcm. We found through an observation by a scanning transmission electron microscope (STEM) that the surface of the wire was covered by Pd particles closely. We also measured the piezoresistance through a change in the distance between Pd particles on a DNA-Pd wire using the DNA tweezers.