Lattice defects in undoped CdAs2 monocrystals

The spectra of optical absorption and photoconductivity of perfect CdAs2 single crystals were investigated near the intrinsic edge and in the extrinsic absorption region. The existence of three donor levels created by structural defects is established. The mechanism of defect formation is suggested: the interstitial Cd-i atom in different charge states created the epsilon(1) < 0.02 eV and epsilon(3) congruent to 0.42 eV levels, the As-v vacancies created the epsilon(2) congruent to 0.26 eV level.