Growth of vertically aligned one-dimensional ZnO nanowire arrays on sol–gel derived ZnO thin films

• ZnO nanowire arrays have been synthesized on sol–gel derived ZnO films.
• Sol–gel derived ZnO films affects the growth of one-dimensional ZnO nanostructures.
• Not only crystalline ZnO but also amorphous one act as a scaffold for ZnO nucleus.
• The morphology of ZnO nanowire arrays are influenced strongly with growth surface.

Vertically aligned one-dimensional ZnO nanowire arrays have been synthesized by a hydrothermal method on sol–gel derived ZnO films. Sol–gel derived ZnO films and corresponding ZnO nanowire arrays have been characterized by X-ray diffraction and field-emission scanning electron microscopy. The effect of sol–gel derived ZnO film surface on the morphology of ZnO nanowire arrays has been investigated. The authors suggest from our investigation that sol–gel derived ZnO films affect the growth of one-dimensional ZnO nanostructures. Not only crystalline ZnO films but also amorphous ones can act as a scaffold for ZnO nucleus. Tilted ZnO micro-rods are grown on ZnO gel films, whereas vertically aligned ZnO nanowire arrays are grown on nanometer-sized ZnO grains. The average diameter of ZnO nanowire arrays are correlated strongly with the grain size of sol–gel derived ZnO films.