Specific Features of Photoluminescence and Nanosecond Relaxation of Photocurrent in CuIn5S8 Crystals upon Strong Optical Excitation

Intense luminescence and nanosecond relaxation of photocurrent upon strong optical excitation have been observed in CuIn5S8 crystals grown by slow melt cooling at a constant temperature gradient. Three emission bands with energies of 1.52, 1.48, and 1.465 eV are distinguished in the photoluminescence spectra. The crystal photoactivation in the range of 300–600 K is explained by an increase in the hole mobility in the valence band with an increase in temperature.