High-quality vertically aligned ZnO nanorods synthesized by microwave-assisted CBD with ZnO-PVA complex seed layer on Si substrates

We successfully synthesized vertically aligned zinc oxide (ZnO) nanorods on seeded silicon substrates using chemical bath deposition assisted by microwave heating. ZnO nanorods were grown on seed layers of ZnO-polyvinyl alcohol (PVA) nanocomposites spin-coated on p-type Si (1 1 1). The nanorod's diameter was found to be dependent on the annealing temperature of the ZnO-PVA seed layer. We produced ZnO nanorods with diameters in the range of 50-300nm from five groups of seed layers annealed at 250 degrees C, 350 degrees C, 380 degrees C, 450 degrees C, and 550 degrees C. The nanorods were examined with X-ray diffraction, transmission electron microscopy, and field emission scanning electron microscopy, which revealed hexagonal wurtzite structures perpendicular to the substrate along the z-axis in the direction of (0 0 2). Photoluminescence measurements revealed high UV emission at a high I-UV/I-vis ratio of 175. We also conducted Raman scattering studies on the ZnO nanorods to estimate the lattice vibration modes. (C) 2011 Elsevier B.V. All rights reserved.