Characterization of a template process for conducting cluster-assembled wires

Bismuth and antimony clusters have been deposited onto spin coated PMMA layers patterned by electron-beam exposure. The probability of reflection or adhesion of the clusters from the PMMA depended on its surface roughness, determined by the electron-beam exposure dose. The Bi and Sb clusters exhibited a significantly higher probability of reflection from unexposed PMMA than from Si3N4 (grown by plasma enhanced chemical vapor deposition) despite the approximately equal surface roughness of these layers. By exploiting this difference in adhesion/reflection, a cluster-assembled wire was grown between four-point planar electrodes. Four-probe electrical measurements yielded linear current-voltage (I(V)) characteristics whilst non-linear I(V) characteristics were obtained from two-probe measurements. An established model provided good agreement with two-probe conductance-voltage and resistance-temperature data. Tunneling barriers between the cluster wire and the planar electrodes are believed to have caused the non-linear two-point I(V) characteristics.