Electrical Conducting Properties of DNA Molecules in a Metal (tip)/DNA/highly Oriented Pyrolytic Graphite Configuration

概要

論文の詳細を見る
We have performed the electrical characterization of DNA molecules in the structure of metal (tip)/DNA/highly oriented pyrolytic graphite (HOPG) using a conducting probe atomic force microscope (CP-AFM). In air, the resistance of DNA is strongly dependent on the contact area of the tip when the tip force is between 0 and 50 nN. At a tip force of 40 nN, the resistances of DNA [Poly(dA–dT)$\cdot$Poly(dA–dT) and Poly(dG–dC)$\cdot$Poly(dG–dC)] were found to be between 1 and 5 M$\Omega$. Under vacuum, the resistance of Poly(dA–dT)$\cdot$Poly(dA–dT) was found to be 0.1 to 0.5 G$\Omega$, approximately one thousand times larger than that in air. By comparing the $I$–$V$ curves of the system on tip/DNA/HOPG and those of the system on tip/SiO2 (thickness of approximately 1 nm)/Si, it was determined that tunneling current existed between the tip and HOPG in the experiment.
2003-05-15