title: Stability of the gold/silica thin film interface: electrochemical and surface plasmon resonance studies.
abstract: This article reports chemical stability studies of a gold film electrode coated with thin silicon oxide (SiOx) layers using electrochemical, surface plasmon resonance (SPR) and atomic force microscopy (AFM) techniques. Silica films with different thicknesses (d = 6.4, 9.7, 14.5, and 18.5 nm) were deposited using a plasma-enhanced chemical vapor deposition technique (PECVD). For SiOx films with d >/= 18.5 nm, the electrochemical behavior is characteristic of a highly efficient barrier for a redox probe. SiOx films with thicknesses between 9.5 and 14.5 nm were found to be less efficient barriers for electron transfer. The Au/SiOx interface with 6.4 nm of SiOx, however, showed an enhanced steady-state current compared to that of the other films. The stability of this interface in solutions of different pH was investigated. Whereas a strongly basic solution led to a continuous dissolution of the SiOx interface, acidic treatment produced a more reticulated SiOx film and improved electrochemical behavior. The electrochemical results were corroborated by SPR measurements in real time and AFM studies.
authors.affiliation: Laboratoire d'Electrochimie et de Physicochimie des Matériaux et des Interfaces (LEPMI), CNRS-INPG-UJF, 1130 rue de la piscine, BP 75, 38402 St. Martin d'Hères Cedex, France. sabine.szunerits@enseeg.inpg.fr
authors.forename: Sabine
authors.initials: S
authors.lastname: Szunerits
authors.forename: Yannick
authors.initials: Y
authors.lastname: Coffinier
authors.forename: Sébastien
authors.initials: S
authors.lastname: Janel
authors.forename: Rabah
authors.initials: R
authors.lastname: Boukherroub
mesh_terms: D004563:Electrochemistry; D006046:Gold / Q000737:chemistry*; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force / Q000379:methods; D010316:Particle Size; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000379:methods*; D013499:Surface Properties
chemical_list: D008567:Membranes, Artificial; D006046:Gold; D012822:Silicon Dioxide