Cadmium Telluride Nuclear Radiation Detectors

The characteristics and performance of undoped high resistivity cadmium telluride detectors are compared to chlorine compensated counters. It is shown, in particular, that "undoped" CdTe Is in fact aluminium doped and that compensation occurs, as in silicon or germanium, by pair and triplet formation between the group III donor and the doubly charged cadmium vacancy (Vcd) acceptor. Furthermore, in chlorine doped samples, the polarization effect results from the unpaired (Vcd) level at Ec -0. 6 eV.