The Study of Thin Films by Electrochemical Impedance Spectroscopy

Abstract

The capabilities and advantages of electrochemical impedance spectroscopy (EIS) as a useful and non-destructive technique are discussed. EIS provides the time dependent quantitative information about the electrode processes. The description of EIS is given in comprehensive way beginning from the theoretical basics of EIS and data interpretation in the frames of various equivalent electric circuits. The practical applications of EIS are described for the following thin film types: (i) cathodic metals/alloys films deposition; (ii) anodization of metals and characterization of oxide films and its growth by EIS including information provided by Mott-Schottky plots; (iii) underpotential deposition of metals; (iv) characterization of organic films onto metals; (v) application in development of biosensors and biofuel cells. The original data of EIS on cathodic electrodeposition of Co and Co-W are provided and reduction mechanisms involving adsorbed intermediates are discussed. The advantages of EIS in the oxide films characterization and their electrochemical properties are shown. EIS can be successfully applied for the characterization of biosensing surfaces and/or in evaluation of bioanalytical signals generated by biosensors. The glucose oxidase (GOx) based biosensor could be successfully analyzed by merged scanning electrochemical microscopy (SECM) and EIS techniques. Such combining study by SECM and EIS could be very attractive in order to evaluate the biofuel cell efficiency and in the modeling of biosensor action, because it is unavailable to obtain by other convenient electrochemical methods.