ABSTRACT
The authors address different aspects of the characterization of materials and devices by small perturbation methods in the frequency domain. Due to the fact that conduction and polarization mechanisms are highly sensitive to the frequency of the external perturbation, the impedance and capacitance spectroscopies provide a great deal of information on carrier accumulation and transport. The authors describe the main characteristics of the frequency-dependent electrical relaxation and transport phenomena that can be observed in organic and inorganic materials. The case of disordered solids, such as ion conducting glasses, introduces a universal behavior of the frequency-dependent conductivity. At low frequency, blocking of ions provides the peculiar response associated with electrode polarization phenomena. To start the analysis of specific applications, let us consider the behavior of a material layer with contacts. If the layer is an insulator that lacks free carriers for conduction, then the capacitance is a dielectric capacitance.
