Excitation and temperature tuned photoluminescence in HgGa2S4 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) = 2.997 eV; a = - 1.34 x 10(-4) eV K-1; b -1.29 x 10(-6) eV K-2] were deduced from PL excitation experiments. (C) 2002 Elsevier Science Ltd. All rights reserved.