Preparation and characterization of bulk ZnGa2O4

Abstract

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 sample 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 °C. It is observed that the single phase of ZnGa₂O₄ has been formed at and above 1000 °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 °C for 24 h which showed 14% Zn, 28% Ga and 58% O, indicating stoichiometric ZnGa₂O₄. 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 ZnGa₂O₄ compound and a mixture of ZnO and Ga₂O₃ powders. Surface morphology studies by scanning electron microscopy reveal that the formation of ZnGa₂O₄ 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.