Electric field induced reversible tuning of resistance of thin gold films

Abstract

The change in resistance of nanostructured metals with respect to an applied field is believed to be due to a change in carrier concentration and hence a linear variation of resistance with the surface charge is expected. In this article, we propose a different approach to explain the resistance variation based on a change in the effective thickness of the film due to a shift of the electron density profile resulting from the applied surface charge. The change in effective thickness together with its effect on surface scattering of electrons account for the majority of the observed variation in resistance. The thin film geometry with different thicknesses and hence a controlled variation of the surface-to-volume ratio allows a deep quantitative understanding and interpretation of the observed phenomena. The model presented in this work shows that a nominal nonlinear response of the resistance of a metal on electrochemically applied surface charge does not necessarily indicate an onset of a redox reaction.