Low-dose radiation effects in extrinsic photoconductors

Experimental results and a model describing long-term radiation-induced cha nges in extrinsic photoconductors are presented. Experiments, carried out a t low temperatures and low photon backgrounds, simulated typical operating conditions of extrinsic infrared detectors used in space- based platforms a nd instruments. The observed changes in the carrier lifetime and current-vo ltage characteristics at a low electric field, as well as a long-term relax ation of the effects after removal of the irradiation are related to a rech arging of the impurities in the bulk during the irradiation. The proposed m odel agrees well with experimental data and despite its simplicity, provide s relevant information on how to deal with these effects in practical appli cations. (C) 1999 American Institute of Physics. [S0021-8979(99)07419-8].