ИСТИНА

The method of obtaining of nanometer scale gaps in metal nanowires based on electromigration of atoms in thin films [1] was realized in this work. Such gaps are of interest for future molecular electronics devices [2], molecular electro-optic elements [3], and the study of magnetoresistance of single molecules [4]. The system and the technique providing a more than 80 % yield of valid gaps (1 – 5 nm) in gold nanowires was developed. The final stage of a gap formation was investigated by measuring a time dependence of a nanowire conductivity. A quantum behavior of conductivity was clearly demonstrated by these measurements. A nanowire conductivity passes through steps with multiple of the fundamental conductivity quantum G0 corresponding to the nanowire’s states with various (decreasing) number of quantum conductivity channels. Resulting gaps were characterized using analysis of their current-voltage characteristics. They were analyzed both in usual and Fowler-Nordheim (F-N) coordinates. It have shown various regimes of electron tunneling through the gap: both a direct tunneling between electrodes and a “cold” emission into a barrier region. Determined from F-N curves values of a gold work function appear to be anomalously low (of about 1 eV). It may be caused by structural degradation/contamination during preparation of nanowires and their electromigration.