Method of solid dielectrics acoustic probing and its capabilities

Abstract

The nondestructive method of electric field probing and polarization in solid dielectrics with acoustic pressure pulses has great possibilities and prospects in investigating the processes and mechanisms of charge transport and slow component of relaxation polarization, which is not displayed by measuring relative dielectric constant at alternating voltage. The experimental procedure and methods of processing the experimental results are being constantly improved. In this case the main problem is the separation of contributions made to the measured signal by space charge and polarization. The most informative way to realize this method is based on the reverse piezoelectric effect, which allows to register fast-running processes of changing the space charge and polarization with a resolution of tens of micrometers. The criteria elaborated allow to estimate the contribution of charge and polarization to the measured signal when probing polar and non-polar dielectrics. The results of the analysis have shown that probing the space charge allows to estimate the value of effective mobility for electrons and holes, and their field dependence, to determine the real value of specific volume electrical conductivity, to determine the contribution of excess and normal charge carriers to the processes of electric transport, and to test the condition of the electrode-sample contact of a dielectric.