Growth and characterization of [001] ZnO nanorod array on ITO substrate with electric field assisted nucleation

This paper reports direct growth of [001] ZnO nanorod arrays on ITO substrate from aqueous solution with electric field assisted nucleation, followed with thermal annealing. X-ray diffraction analyses revealed that nanorods have wurtzite crystal structure. The diameter of ZnO nanorods was 60–300 nm and the length was up to 2.5 μm depending on the growth condition. Photoluminescence spectra showed a broad emission band spreading from 500 to 870 nm, which suggests that ZnO nanorods have a high density of oxygen interstitials. Low and nonlinear electrical conductivity of ZnO nanorod array was observed, which was ascribed to non-ohmic contact between top electrode and ZnO nanorods and the low concentration of oxygen vacancies.