Influence of the Spray Pyrolysis seeding and growth parameters on the structure and optical properties of ZnO nanorod arrays

JUAN RODRÍGUEZ; GUY FEULLIET; FABRICE DONATI; DIEGO ONNA; LUIS SÁNCHES; ROBERTO CANDAL; MARÍA CLAUDIA MARCHI; SARA ALDABE BILMES; FREDERIC CHANDEZON

MATERIALS CHEMISTRY AND PHYSICS

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2015 vol. 151 p. 378 - 384

0254-0584

ZnO nanorods (NRs) were grown on fluorine doped tin oxide (FTO) substrates at low temperatures(90 C) from Zn2þ precursors in alkaline media previously seeded with ZnO nanoparticles. These weredeposited onto the FTO substrate heated at 350 C by spray pyrolysis of a Zn acetate solution in a waterethanol mixture. The structure of seeds was tuned by the ethanol to water ratio, G, which controls thesolvent evaporation rate of drops impinging the substrate. From a detailed characterization using acombination of scanning electron microscopy, X-ray diffraction, UVevisible absorption and cathodoluminescencespectroscopies, the dependence of the morphology and optical properties of the ZnONRs on the seeding conditions was demonstrated. NRs grown on seeds deposited from solutions with G in the 0.03e0.06 range e i.e. when the surface excess of ethanol in the watereethanol mixture has a maximum e show thinner average diameters and stacking faults due to the presence of zinc blende domains embedded into an overall wurtzite NR. They furthermore exhibit blue-shifted near band edge emission peak and a high deep level emission in cathodoluminescence. All these findings support the use of spray pyrolysis as a simple and reproducible way to control the seeds deposition, influencing the growth, the structure and the optical properties of the final ZnO NRs.