Dependence of the properties of hydrothermally grown ZnO on precursor concentration

This study evaluated the effects of precursor concentration ranging from 0.06 to 1.5 M on the properties of hydrothermally grown ZnO on annealed ZnO buffered Si substrates. At relatively low concentrations (no more than 0.5 M), well-aligned ZnO arrays were grown on ZnO/Si(1 0 0) due to heterogeneous nucleation. As the concentration was increased to 1.0 M, the morphologies changed to randomly accumulated particles as a result of homogeneous nucleation. The crystal and optical properties of the materials were investigated by X-ray diffractometer (XRD) and photoluminescence (PL) measurement, respectively. It was found that the best crystal and optical properties were obtained with concentrations of 0.5 and 0.3 M, respectively. These properties were observed to degrade when the concentration was raised to more than 1.0 M.