Charge transport and conductance oscillations in gold island films

Current-voltage measurements including first- and second-derivative measurements have been obtained from gold island films for temperatures between 10 and 300 K. The experimental results and an empirical analysis of the steady-state current as a function of bias voltage and temperature [$I=f(V,T)\mathrm{}$] yield a parabolic current-voltage law and a linear conductance-temperature dependence. These results are unusual, but by using a numerical approximation they may be interpreted as arising from a network of nonlinear tunnel junctions. The observation of large oscillations in the second-derivative current-voltage spectra near zero bias voltage suggests a resonant tunneling process between localized states a few meV below the insulator conduction-band edge.