Characterization of ZnO nanorod arrays fabricated on Si wafers using a low-temperature synthesis method

ZnO nanorod arrays fabricated on ZnO buffer layers on Si wafers were grown using a low-temperature solution method and were characterized by various techniques. Buffer layers were prepared using metal organic chemical vapor deposition and a sputter-oxidation method. Aligned ZnO nanorods were deposited at 90°C on the substrates by a hydrothermal treatment using a zinc salt and aqueous ammonia solution. The ZnO nanorod arrays were characterized by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, Raman spectroscopy, and photoluminescence spectroscopy. The as-grown ZnO nanorod arrays exhibited broad deep-level emission centered at ∼564nm. The intensity of the deep-level emission decreased and band edge emission centered at 379nm appeared after air annealing. Samples annealed in hydrogen showed only band edge emission.