Abstract

In situ spectroscopic ellipsometric measurements have been carried out on a gold electrode in an electrolyte under a dc electric field. An intermediate layer which begins to form just above the threshold potential of the oxidation of gold has been detected and characterized in terms of its optical properties and thickness. It is confirmed with the aid of computer simulation that the effect of the redistribution of the ions in liquid and the electrons in gold electrode on the ellipsometric parameters Δ and ψ has a minimal effect compared with the experimental results. Even though the intermediate layer at the S/L interface revealed some properties which are characteristics of metals, a simple model based on the modulation of gold under a dc electric field turned out to be unable to explain quantitatively the experimentally observed changes of δΔ and δψ.

© 1987 Optical Society of America