Preparation and characterization of bulk ZnGa2O4

High-quality bulk ZnGa2O4 has been synthesized from equimolar mixtures of Z nO and Ga2O3 by the conventional solid-state method. For the first time, th e sam pie has been characterized in detail to confirm the formation of pure single phase of spinel ZnGa2O4. The formation of ZnGa2O4 has been confirme d by sintering the mixtures of ZnO and Ga2O3 at different temperatures, ran ging from 900-1200 degrees C. It is observed that the single phase of ZnGa2 O4 has been formed at and above 1000 degrees C sintering temperature for 24 h. The crystallinity and phase formation of this single phase has been con firmed by X-ray diffraction. X-ray photoelectron spectroscopic studies have been carried out for bulk ZnGa2O4 sintered at 1000 degrees C for 24 h whic h showed 14% Zn, 28% Ga and 58% O, indicating stoichiometric ZnGa,O,. A new parameter, the energetic separation between the Zn 2p(3/2) and Ga 2p(3/2) peaks, has been used as a sensitive tool to distinguish between a complete formation of ZnGa,O, compound and a mixture of ZnO and Ga,O, powders. Surfa ce morphology studies by scanning electron microscopy reveal that the forma tion of ZnGa,O, takes place in mosaic rod-like structure. The purity of the compound has also been checked by the energy dispersive X-ray method, indi cating the absence of foreign ions and the ratio of zinc to gallium has bee n calculated and found to be 1:2, indicating stoichiometric ZnGa2O4. (C) 19 98 Kluwer Academic Publishers.