Formation of complete solid solutions, Zn(AlxGa1−x)2O4 spinel nanocrystals via hydrothermal route

Spinel-structured complete solid solutions: Zn(AlxGa1−x)2O4, x=0-1.0 were directly formed as nanocrystals from the aqueous precursor solutions of inorganic metal salts under hydrothermal conditions at 240 °C for 5 h in the presence of tetramethylammonium hydroxide. The crystallite size of the spinel varied from 14.5 to 5 nm with increased Al atomic ratio, x in the composition from x=0 to 1.0. The linear decrease in the lattice parameter of the spinel phase by the substitutional incorporation of Al into the lattice nearly followed the Vegard׳s law though a slight positive departure from the law was observed. The incorporation of Al into the lattice, Zn(AlxGa1−x)2O4 resulted in wider optical band gap due to the blue shift of absorption spectra. The broad-band UV-visible blue light emission centered at around 480 nm that was observed under excitation at 270 nm Xe lamp in the ZnGa2O4 spinel showed blue shift by the incorporation of Al into the lattice, Zn(AlxGa1−x)2O4.