Correlated single electron transport in capacitively coupled tunnel junction arrays

This dissertation is a study of single electron transport in capacitively coupled arrays of small area tunnel junctions. The tunnel junctions were fabricated using electron beam lithography and a double angle-shadow evaporation technique. In the normal state of a single array, Coulomb blockade and single electron transport are shown to be the dominant mechanisms. The current-voltage (I-V) characteristics of the individual arrays in the superconducting state showed multiple negative differential conductance (NDC) regions. The NDC could be understood in terms of transport involving both cooper pairs and quasiparticles. Evidence of quasiparticle co-tunneling processes was also observed. The coupled arrays in the normal state also showed negative differential conductance at low bias voltages, which is attributed to the electron trapping and de-trapping in one of the arrays. Near the coulomb blockade threshold voltage, the arrays showed evidence of correlated transport and current mirroring.