Development of physico-chemical models for electrochemical impedance spectroscopy

An integrated approach to electrochemical impedance spectroscopy

“…Orazem et al [11] and Jansen et al [12] described the impedance response for an n-type GaAs Schottky diode with temperature as a parameter. The system consisted of an n-GaAs single crystal with a Ti Schottky contact at one end and a Au, Ge, Ni Schottky contact at the eutectic composition at the other end.…”

“…This material has been well characterized in the literature and, in particular, has a well known EL2 deep-level state that lies 0.83-0.85 eV below the conduction band edge [13]. Experimental details are provided elsewhere [11,12].…”

“…Impedance data as a function of frequency for an n-GaAs/Ti Schottky diode with temperature as a parameter: (a) the real part of the impedance; and (b) the imaginary part of the impedance. Data taken from Orazem et al [11] and Jansen et al [12]. a normalized frequency defined by…”

“…Regression analysis using the traditional weighting strategies under which the standard deviation of the experimental values was assumed to be proportional to the modulus of the impedance, σ r = σ j = α|Z|, to the magnitude of the respective components of the impedance, σ r = α r |Z r | and σ j = α j |Z j |, or independent of frequency, σ r = σ j = α, yielded one dominant RC time constant with only a hint that other parameters could be extracted. Orazem et al [11] and Jansen et al [12] used the measurement model approach described by Agarwal et al [5][6][7] and Orazem [8] to identify the stochastic error structure for the impedance data. When the data were regressed using this error structure for a weighting strategy, additional parameters could be resolved revealing additional activation energies.…”

Alternatives to Kronig-Kramers transformation and testing, and estimation of distributions

“…Although the use of the top circuit (without the Cp, CD, and R D elements) has been recently usefully advocated for preliminary "measurement model" data fitting [ 31,32], these DRT or DAE circuits have been used for fitting for many years. But only relatively recently, with the availability of powerful CNLS fitting programs, has it become straightforward and practical to fit data to such equivalent circuits when M is appreciable.…”