Electrical conductivity measurement of DNA double-stranded chains by "one-by-one" cutting method using atomic force microscopy

We measured the electrical current-voltage characteristics of ADNA in vacuum using fine electrodes with a gap of about 200 nm. It was found that the electrical resistance of ADNA molecules between the fine electrodes had a large variation: from 7.8 M Omega to values larger than 1 T Omega. This was consistent with the controversial results given in previous reports. The temperature dependence of conductivity was explained well by the Arrhenius equation. In addition, the conductivity of a single molecule of double-stranded A DNA was measured by a "one-by-one" cutting method using atomic force microscopy (AFM). The conductivity was determined to be 3 x 10(1) S/cm, which is about the same order as that of semiconductors.