Preparation and characterization of bulk ZnGa2O4

High-quality bulk ZnGa2O4 has been synthesized from equimolar mixtures of ZnO and Ga2O3 by the conventional solid-state method. For the first time, the sam pie has been characterized in detail to confirm the formation of pure single phase of spinel ZnGa2O4. The formation of ZnGa2O4 has been confirmed by sintering the mixtures of ZnO and Ga2O3 at different temperatures, ranging from 900-1200 degrees C. It is observed that the single phase of ZnGa2O4 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 confirmed by X-ray diffraction. X-ray photoelectron spectroscopic studies have been carried out for bulk ZnGa2O4 sintered at 1000 degrees C for 24 h which 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. Surface morphology studies by scanning electron microscopy reveal that the formation 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, indicating the absence of foreign ions and the ratio of zinc to gallium has been calculated and found to be 1:2, indicating stoichiometric ZnGa2O4. (C) 1998 Kluwer Academic Publishers.