Radical-recombination luminescence, ion-luminescence and photoluminescence of CaGa2S4:Eu Original Research Article

CaGa2S4 based luminophors have recently attracted significant attention due to their high efficiency. Very little is known now about the surface and near surface luminescence of these luminophors. The ion-luminescence of CaGa2S4:Eu excited by low energy hydrogen ions (up to 3 keV) and the radical-recombination luminescence excited by neutral hydrogen atoms of thermal energies have been studied. The latter is due to chemical energy released at the surface during heterogeneous recombination of atoms into molecules (∼4 eV per recombination event). The radical-recombination luminescence is likely the most surface kind of luminescence, while the ion-luminescence is the luminescence of near-surface layers. In this regard the photoluminescence is the bulk one of with which the characteristics of the surface luminescence might be compared.