Electron-Electron Interaction Dominated Resistivity Minimum In Quasi-Continuous Ag Nanocluster Films

Electronic transport in metal nanoclusters has great significance due to a variety of tunable parameters such as size, dimensionality, and cluster-distribution. Here, we report on the resistivity behavior of randomly distributed quasi-continuous Ag nanocluster films of varying cluster coverage on the substrate. This was achieved by changing the deposition time of clusters on the substrate. The Ag nanoclusters which were about 15 nm in size were deposited on thermally oxidized silicon substrates. As the deposition time reduced, clusters were distributed randomly with less coverage on the surface, resulting in a resistivity minimum at low temperatures. The temperature at which resistivity minimum occurs increases as the deposition time decreases. The resistivity at temperatures above 45 K was found to fit with a modified Bloch-Gruneisen equation which includes interaction of electrons due to structural disorder. However, the obtained Debye temperatures were found to decrease in comparison with the bulk values, which is ascribed to the softening of phonon modes in these structures. The emergence of the resistivity minimum could be explained through disorder effects in electron-electron interaction dominated quantum corrections, as shown in the Altshuler-Aronov model. A T-1/2 temperature dependence of resistivity at low temperatures, as predicted by this model, was observed in our system, showing the applicability of this model.