PHYSICAL GROUNDS OF HIGH-SENSITIVE ROOM-TEMPERATURE DETECTION OF INFRARED RADIATION INVOLVING SPHERICAL EXCITONS AT IMPURITIES IN CRYSTALS

The possibility of the IR-radiation detecting in crystals of direct-ga p semiconductors, caused by effects of IR-quenching of probe visible-r ange radiation within the region of a crystal relative transparency, i s studied both theoretically and experimentally. The comparison of som e mechanisms investigated allows to conclude that the most probable ex planation of the IR-quenching effect, experimentally observed in the C dS crystal, is the mechanism of probe radiation absorption with photon energy ''deficit'' with respect to exciton resonance, which is elimin ated due to exchange interaction of a free exciton in the intermediate state with spherical excitons localized on manyelectron atoms of impu rity.