Investigation of the electrical properties of metallic nanoclusters

Palladium nanoclusters were prepared by magnetron sputtering and inert gas condensation technique and deposited between two gold electrodes. We have investigated the current-voltage characteristics at temperatures between 45 and 300 K. The conduction-voltage profile allows calculating the number of potential barriers, n electrons have to cross while conducting through a percolation path. n is found to increase with decreasing temperature. The observed temperature dependence of the conductance is Arrhenius-like above 140 K, with activation energy much smaller than the calculated Coulomb blockade energy. It suggests that some of the nanoclusters are fused together. At temperatures below 140 K the conductance-temperature data was fitted with Efros-Shklovskii model for conduction where variable range hopping is dominating the electron transport mechanism. The presence of variable range hopping may interpret the increase of n with decreasing temperature.