Defects introduced in cadmium telluride by gamma irradiation

The properties peculiar to high resistivity CdTe:Cl are of great interest b ecause of its application as a radiation detector. The compensation process responsible for the materials semi-insulating character implies the presen ce in the lattice of impurities and defects which have not yet been thoroug hly characterized. The use of CdTe:Cl as a detector exposes the material to high fluxes of ionizing radiation which alter the crystal stoichiometry an d affect the resulting electrical and optical properties, but few and scatt ered experimental data are available about radiation effects on this compou nd. In this work we have carried out an extensive investigation of the effe cts of gamma irradiation on CdTe:Cl by photoinduced current transient spect roscopy analyses. We have identified the deep levels with activation energi es up to midgap and we have followed their evolution with increasing irradi ation doses up to 50 kGy, the dose which totally degrades the material dete cting properties. (C) 2001 American Institute of Physics.