Fabrication and optical properties of highly oriented ZnO nanorod array films

Transparent and compact ZnO nanorod array films were fabricated on indium tin oxide glass substrate by a potentiostatic electrodeposition method in Zn(NO3)2 solution using adding hexamethylenetetramine as shape control agent. The morphology and structure of the ZnO films were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy, transmittance and photoluminescence spectra of the ZnO films were measured. The results indicate that the as-synthesized ZnO nanorod films with high c-axis preferred orientation possess a high-quality single-crystal wurtzite structure, their average grain diameter is about 200 nm, and the crystalline degree and surface smoothness of the ZnO nanorod films obviously increase. The transmittance of the ZnO films is more than 80% in the visible region, and has a steep absorption edge. The photoluminescence spectra at room temperature show that a strong and sharp ultraviolet emission peak and a weak green emission peak of the ZnO films are located at 380 and 510 nm, respectively.