ELECTRICAL-PROPERTIES OF DISCONTINUOUS METAL-FILMS ON SAPPHIRE SUBSTRATE NEAR THE PERCOLATION-THRESHOLD

The results of measurements of some or the electrical properties of discontinuous metal Rims on sapphire substrates near the percolation threshold are presented. The properties were investigated below and above this threshold, i.e. in the insulating region and in the metallic region of conduction. The appearance of the first continuous path connecting the electrodes of the sample entirely changes its electrical properties. The character of the electron transport in such a film changes from thermally activated tunnelling to metallic type conduction, which is manifested by drastic changes in many physical quantities characterizing these films (e.g. resistance, noise power, and temperature coefficient of resistance). © 1990 Taylor & Francis Ltd.