| Crystal Research and Technology |
Electrical properties of discontinuous Pt films were investigated. Pt films with different coverage coefficients (p) were evaporated onto quartz-glass substrates under vacuum conditions (p ≈10-4Pa). The temperature dependencies of resistance measured in vacuo in situ made possible to determine the activation energy of resistance for the films. These values of activation energy were compared with those obtained on the basis of structural examinations conducted by means of electron microscope. The dependencies of the island diameters and of the gaps on coverage coefficient were determined for examined films. The log of resistance of Pt films versus coverage coefficient was also presented. It has been found that the electrical properties of the film are subject to change near the percolation threshold. This behaviour is attributed to a change in the type of conduction. Films with coverage coefficient p < pC (pC is the critical coverage coefficient) exhibit high resistance, their activation energy of resistance decreases with metal content increase. For p > pC the resistances reach lower values, the activation energies of resistance are near to zero. The conduction mechanisms in discontinuous Pt films are proposed.
Keywords: discontinuous Pt films, electrical conduction mechanisms, electrical properties