Polarization in Cadmium Telluride Nuclear Radiation Detectors

Polarization has been studied in semi-insulating cadmium telluride compensated with chlorine. Several parameters have been considered including surface preparation, nature of the contact, temperature, as well as type and strength of the source. A model that assumes that the space charge region is produced by injected electrons being trapped by deep acceptors explains most of the effects observed. The possible nature of the center is discussed. Finally it is demonstrated that MIS structures are also a practical means to suppress the polarization.