Observation of single-electron charging effects in small tunnel junctions

Unusual structure and large electric-field--induced oscillations have been observed in the current-voltage curves of small-area tunnel junctions arranged in a low-capacitance (\ensuremath{\lesssim}1 fF) multiple-junction configuration. This behavior arises from the tunneling of individual electrons charging and discharging the capacitance. The observations are in accord with what would be expected from a simple model of the charging energies and voltage fluctuations of e/C associated with such effects.