Excitation and temperature tuned photoluminescence in HgGa2S4 single crystals

Abstract

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 0K 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.