Correlation between the crystalline environment and optical property of Mn2+ ions in ZnGa2O4: Mn2+ phosphor -: art. no. 091912

Sol-gel-driven ZnGa2O4:Mn2+ phosphors are annealed at various temperatures. As an increase of the annealing temperature of as-grown ZnGa2O4:Mn2+ phosphors, their lattice constants and crystallinities are increased. The resonance signal intensity of Mn2+ ions on T-d sites is drastically increased whereas that of Mn2+ ions on O-h sites is decreased as the annealing temperature is increased. The decay curves are well fitted with two simple exponential decay functions indicating the existence of two origins. Liquid nitrogen-temperature emission spectra show two emission peaks suggesting that they originate from Mn2+ ions on T-d and on O-h sites. The emission intensity of Mn2+ ions on T-d sites is drastically increased whereas that of Mn2+ ions on O-h sites is decreased. The. variation of the optical characteristics agrees with the concentration of Mn2+ ions at T-d site and its site environment. (C) 2005 American Institute of Physics.