ELECTRONIC-PROPERTIES OF CHLORINE DOPED CADMIUM TELLURIDE USED AS HIGH-ENERGY PHOTOCONDUCTIVE DETECTOR

A new high energy X-ray chlorine doped cadmium telluride (CdTe:Cl) photoconductor is described. We discuss different deposition techniques (sputtering, evaporation, electroless) to realize ohmic contacts which have low leakage current and which allow high applied electric field. The temperature dependence of the dark current gives an activation energy of 0.6 eV for standard CdTe:Cl. The transient response of photoconductors under high X-ray energy beams has been characterized using three different pulse durations; 150 ps, 30 ns and 4 mus. Sensitivity and speed of response are studied as a function of neutron preirradiated doses (0, 10(14), 10(15), 10(16) n/cm2): neutron irradiations reduce the carrier lifetime at the expense of a lower sensitivity.