Structural and electrical properties of an Au film system deposited on silicone oil surfaces

Abstract

An Au thin film system, deposited on silicone oil surfaces by the thermal deposition method, has been fabricated and its structure as well as electrical properties has been studied. A web-shaped characteristic surface morphology of the films is observed. The dc sheet resistance R of the metal films on the liquid surfaces is measured during and after deposition in situ by the four-probe method. The time dependence of the sheet resistance can be explained in terms of the film growth mechanism on the oil surface. The anomalous I–V characteristics of the film system can be interpreted as a competition among the local Joule heating, hopping and tunnelling effects. It is found that the dc third-harmonic coefficient B0 and the zero-power resistance R0 satisfy the power-law relation B0 ∝ R02+w and the exponent w is close to zero. This result indicates that the hopping and tunnelling effects in the samples are much stronger than those of the other film systems. We also find Im ∝ R0−β with β = 0.79 ± 0.08 and Im ∝ B0−γ with γ = 0.49 ± 0.07, where Im is the critical current. The physical origins of the phenomena are discussed.