SINGLE-ELECTRON-TUNNELING EFFECT IN NANOSCALE GRANULAR MICROBRIDGES

The single-electron-tunneling (SET) effect in a nanoscale granular mic robridge, which consists of a two-dimensional array of small intergrai n tunnel junctions, was investigated. We observed the Coulomb blockade effect and the periodic electrical field effect in the microbridges. These results coincide well with results of numerical calculations bas ed on a model of a two-dimensional SET junction array. We shelved that electron conduction properties of the microbridges are quasi-zero-dim ensional, because the size of the charge soliton is larger than the di mensions of the microbridges. The details of the current-voltage chara cteristics were considered as an aspect of the Kosterlitz-Thouless (KT ) transition, which is a peculiar phase transition in a two dimensiona l system. The electron conduction properties are extremely affected by the existence of a fixed background charge.