Research study of volt-amperage properties (VAP) of [Formula: see text] crystals determined the mechanism of current flow though the studied samples and this mechanism is based on barrier Schottky emission and emission of Franklin–Paul. The dielectric constant of the material, height of the potential barrier on metal–semiconductor border, concentration of the traps and the effective mass of electrons are calculated.

The investigation of photoluminescence (PL) properties of Ca(Al[Formula: see text]Ga[Formula: see text]S4:Eu[Formula: see text] solid solutions with [Formula: see text] = 0, 0.1, 0.2 and 0.3 synthesized for the first time was performed in wide temperature and excitation power density ranges. It is shown that PL intensity decreases by only 20–30% for different [Formula: see text] in the temperature range from 10 K to 300 K. The extreme stability of shape and position of the emission spectra was found in the range of excitation power density from [Formula: see text] W/cm2 to [Formula: see text] W/cm2 by nanosecond pulsed radiation. The reversible PL efficiency droop was only above 104 W/cm2 of excitation power density. The PL decay time constant was found to be of about 560 ns to 595 ns for [Formula: see text] ranging between 0.1 and 0.3 at room temperature.