Excitation and temperature tuned photoluminescence in HgGa 2 S 4 single crystals

Mercury thiogallate single crystals are shown to exhibit bright photoluminescence (PL) tunable in a wide spectral range from green to red when changing the excitation power density, wavelength and sample temperature. Taking into account the excitation and temperature dependencies of the PL characteristics, a model accounting for the radiative electron transitions in HgGa2S4 is proposed. The values of the energy gap extrapolated to 0 K and of the linear and quadratic temperature coefficients of the energy gap [Eg(0)=2.997eV;a=−1.34×10−4eVK−1;b=−1.29×10−6eVK−2] were deduced from PL excitation experiments.