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DNA (Deoxyribonucleic acid) has recently caught the attention of chemists and physicists. A major reason for this interest is DNA’s potential use in nanoelectronic devices, both as a template for assembling nanocircuits and as an element of such circuits. However, the electronic properties of the DNA molecule remain very controversial. Charge-transfer reactions and conductivity measurements show a large variety of possible electronic behavior, ranging from Anderson and band-gap insulators to effective molecular wires and induced superconductors. In this review article, we summarize the wide-ranging experimental and theoretical results of charge transport in DNA. An itinerant electron model is suggested and the effect of the density of itinerant electrons on the conductivity of DNA is studied. Calculations show that a DNA molecule may show conductivity from insulating to metallic, which explains the controversial and profuse electric characteristics of DNA to some extent.

Electric transport of DNA is closely related to the itinerant π-electrons due to the soft characteristic of DNA molecules. We suggest a model with adjustable number itinerant electrons (ANIE). The density of states (DOS), the transmission coefficient and the electric conductance were studied. It was found that the conductance depends sensitively upon the number of the itinerant electrons. Resistivity of Poly(dG)-Poly(dC) was obtained, which is well consistent with the experimental data.

Due to the excellent optical and electrical properties, ZnO thin films deposited on flexible substrates can be used as technologically promising electron devices. Polytetrafluoroethylene (Teflon) had many advanced properties, such as high dielectric strength over various frequencies, low dissipation factor, and high surface electrical resistivity, which had made Teflon a competitive polymer choice in a variety of microelectronic applications. In our work, ZnO film was firstly deposited on Teflon substrate by the magnetron sputtering method. X-ray diffraction data revealed that the ZnO grains were highly c -axis-oriented and nanostructured with the size of 10–30 nm, which was in accordance with the experimental result of Scanning Electron Microscopy.

The electrical transport of DNA is closely related to the density of itinerant pi electrons because of the strong electron-lattice interaction. The resistivities of two typical DNA molecules [poly(dG)-poly(dC) and lambda-DNA] with varied densities of itinerant pi electrons are calculated. It is found that the dependence of the resistivity on the density of itinerant pi electrons is symmetrical about the half-filling state of itinerant pi electrons in poly(dG)-poly(dC). At the half-filling state, the Peierls phase transition takes place and poly(dG)-poly(dC) has a large resistivity. When the density of itinerant pi electrons departs far from the half-filling state, the resistivity of poly(dG)-poly(dC) becomes small. For lambda-DNA, there is no Peierls phase transition due to the aperiodicity of its base pair arrangement. The resistivity of poly(dG)-poly(dC) decreases with increasing length of the molecular chain, but the resistivity of lambda-DNA increases with increasing length. The conducting mechanisms for poly(dG)-poly(dC) and a few lambda-DNA molecules with varied densities of itinerant pi electrons are analyzed.