xxiii πανελληνιο ÏƒÏ Î½ÎµÎ´ÏÎ¹Î¿ Ï†Ï ÏƒÎ¹ÎºÎ·Ï‚ στερεας καταστασης & επιστημης ...

Investigation of the Structural, Morphological and Photocatalytic Properties of ZnO
Thin Films and Nanostructures Deposited by Different Chemical Routes
G. Kenanakis 1,2,3,4 , Z. Giannakoudakis 3 , D. Vernardou 1,2,5 , E. Koudoumas 1,6 and N. Katsarakis 1,2,4 *
1 Center of Materials Technology and Laser, School of Applied Technology, Technological Educational Institute of Crete,
710 04 Heraklion, Crete, Greece
2 Science Department, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete,
Greece
3 University of Crete, Department of Chemistry, 710 03 Heraklion, Crete, Greece
4 Institute of Electronic Structure and Laser, Foundation for Research & Technology-Hellas, P.O. Box 1527, Vassilika
Vouton, 711 10 Heraklion, Crete, Greece
5 University of Crete, Department of Materials Science and Technology, 710 03 Heraklion, Crete, Greece
6 Electrical Engineering Department, Technological Educational Institute of Crete, 710 04 Heraklion, Crete, Greece
*katsan@iesl.forth.gr
Over the past years, the synthesis of ZnO has been the subject of intense research due to its potential applications in
transparent conducting thin films, ultraviolet emitting diodes, gas sensors and photocatalysts. In this work, ZnO
nanostructures and thin films were synthesized by chemical route techniques. The fabrication of versatile ZnO nanostructures
with controlled morphology and high surface-to-volume ratio was achieved by aqueous chemical growth, a novel, simple,
environmental-friendly and inexpensive method for depositions at mild temperatures. ZnO thin films were obtained either
using a sol-gel / spin-coating method or ultrasonic spraying pyrolysis. All samples were characterized using x-ray diffraction
(XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and UV - visible spectroscopy. It is revealed
that the wurtzite ZnO structure is the only crystallographic phase detectable in all cases. The shape and the dimensions of the
nanostructures were found to depend on the growth time and the concentration of the precursor solution. It is seen that ZnO
nanostructures transform from flowerlike to rod like by altering the concentration from 10 -2 M to 10 -3 M at 95 o C.
Transmittance measurements have shown that the ZnO films are transparent in the visible wavelength region and their energy
gap was calculated. Finally, their photocatalytic properties are investigated and discussed over a wide range of growth
parameters.
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