Synthesis, characterization and optical properties of flower-like ZnO nanorods by non-catalytic thermal evaporation

Well-crystallized with excellent optical properties, flower-like zinc oxide (ZnO) nanorods have been successfully synthesized on Si(1 1 1) substrates using a pulsed laser deposition (PLD) prepared Zn film as "self-catalyst" by the simple thermal evaporation oxidation of the metallic zinc powder at 800 degrees C without any other catalysts or additives. The pre-deposited Zn films by PLD on the substrates can promote the formation of the ZnO nuclei effectively. Also it can further advance the growth of flower-like ZnO nanorods accordingly. A number of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectrum (FTIR) and photoluminescence (PL) were used to characterize the structural and optical properties of the obtained ZnO nanorods. The results indicate that the nanorods are highly crystalline with the wurtzite hexagonal phase, grown along the [0 0 0 1] in the c-axis direction. The PL spectrum showed that the as-synthesized ZnO nanorods showed UV (383 nm) and green (512 nm) emission, respectively. In addition, the growth mechanism of the ZnO nanorods are discussed based on the reaction conditions. (C) 2009 Elsevier B.V. All rights reserved.