Dependence of the structural and the optical properties of ZnGa2O4 phosphors on the mixture molar ratio of ZnO and Ga2O3

Dependence of the structural and the optical properties of ZnGa2O4 phosphors on the mixture molar ratio of ZnO and Ga2O3 were investigated by using X-ray diffraction (XRD) and cathodoluminescence (CL) measurements. While the lattice constants of the ZnGa2O4 phosphors obtained from the XRD curves varied dramatically with changing the excess amount of the ZnO, those did not change significantly with increasing the excess amount of the Ga2O3. The CL spectra exhibited the dominant emission peak in the ZnGa2O4 shifted to the longer wavelength with increasing the amount of the ZnO excess and that the peak position of the emission was not independent on the variation quantity of the Ga2O3 excess. This result indicates that the ZnO excess in the ZnGa2O4 phosphors has a limit solubility and that the Ga2O3 excess is not soluble in the ZnGa2O4 phosphors. (C) 2001 Elsevier Science Ltd. All rights reserved.