Electron transport in nanocluster films with random voids

Nanocluster films are modeled as a network of tunnel junctions in which random voids have been introduced. The effects of network size and void distribution on electron transport are studied using Monte Carlo simulations of the Coulomb blockade mediated transport. The random void distributions of the model networks are systematically varied by randomly deleting junctions along each row and between the different rows. The nonlinearity and voltage threshold of the I-V curves are calculated for different void topologies and network sizes. Both the threshold voltage and nonlinearity are sensitive to lateral fluctuations of the conduction paths due to the random voids. The nonlinearity is found to be maximized for network aspect ratios of unity or larger and for particular network topologies. Both the nonlinearity and voltage threshold scale with network size. The behaviors seen in simulation are found to correspond well to Au nanocluster I-V measurements.