Growth, structure and photoluminescence properties of SnO₂-ZnO (TZO) micro cubes

Structural investigation from X-ray diffraction patterns of TZO revealed the presence of SnO₂ (cassiterite), ZnO (wurtzite) and ZnSnO₃ and ZnSnO₄ phases. The optical absorption spectra recorded for these powders dispersed in ethanol show the nature of the composite nanopowders to be semiconducting one having an optical absorption band around 280 nm. Electron microscopy confirms a change in shape and size of the particles with a change in Sn/Zn ratio. The amorphous nature increases while going from Sn/Zn ratio of 0.87 to 3.75 and cubes of size ∼ 2μm, rhombohedral and irregular shaped particles are also observed. The prepared tin zinc oxide samples (TZO) show excitation bands at 241, 287 and 351 nm and common emission bands at 448, 485, 462 and 531 nm for all excitation energies. The photoluminescence and other studies reveal the role played by composition in changing the shape. (paper)