Optical and photoelectric properties of gamma-irradiated GaS:Er3+ layered crystals

Erbium doping (0.1, 0.15, 0.20 at % Er) markedly increases the photosensitivity and photoluminescence (PL) intensity of GaS crystals. Most likely, erbium substitutes on the gallium site. Irradiation with low gamma doses increases the photosensitivity and PL intensity of the crystals, broadens their PL spectrum, and shifts the PL peaks to longer wavelengths. It seems likely that the radiation-induced recombination centers consist of gallium vacancies and erbium atoms. The concentration of such defect complexes depends on the gamma dose.