LOW-FREQUENCY ELECTROMECHANICAL RELAXATION IN PIEZOELECTRIC SEMICONDUCTORS

The attenuation of elastic waves in the kilohertz range by free charge carriers in high-resistivity piezoelectric semiconductors has been si mulated numerically. The results are reported. The attenuation charact eristics depend on the relation between the Debye screening length and the dimensions of the sample. A change in the conductivity of the sam ple causes a shift of the attenuation peak along the temperature scale without changing the height of this peak. It is concluded that a Maxw ellian relaxation mechanism is insufficient to explain the features of the electromechanical relaxation found in previous experiments on III -V and II-VI materials compensated through the introduction of deep ce nters.