Open AccessPoint Defect Model Description of the Formation of Anodic Gold Oxide in H2SO4 Solution
Author(s) -
Zahed Ghelichkhah,
Gregory S. Ferguson,
Digby D. Macdonald,
Samin SharifiAsl
Publication year - 2021
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/abf409
Subject(s) - oxide , ellipsometry , analytical chemistry (journal) , dielectric spectroscopy , materials science , electrochemistry , anode , chemistry , thin film , metallurgy , electrode , nanotechnology , chromatography
An impedance-based Point Defect Model (PDM) was developed for the potentiostatic, anodic formation of gold oxide at potentials of 1.40–1.70 V vs SHE in H 2 SO 4 (0.1 M and 0.5 M). Film thickness and refractive indices were determined at each oxide formation potential using spectroscopic ellipsometry. The thickness of the oxide increases linearly with increasing potential. Mott-Schottky analysis shows that the oxide exhibits both n-type and p-type character and the dominant defect density is calculated to be in the order of 10 21 −10 22 (1 cm −3 ). The PDM was optimized upon experimental EIS data to extract values for model parameters and accounts well for the experimental observations in both the steady-state time and frequency domains.