The spectrum of the transient photoinduced optical absorption (PA) in trigonal single-crystal selenium is reported. Three components of the PA spectrum are distinguished. The first two arise from the excited state of the center that gives rise to the mid-gap photoluminescence. One of these may be the result of photon-assisted hopping of self-trapped excitons. The other may arise from photoionization of electron polarons from the potential well caused by the distortion around them. The last component decays very slowly and has a distribution of time constants. It is identified as the optical ionization of electrons from traps which are probably defect related.

• Received 25 July 1985

DOI:https://doi.org/10.1103/PhysRevB.33.1073