ZnO Nanowire Arrays Grown by Electrophoretic Deposition Technique from Colloidal Suspensions of ZnO nanoparticles

TIRADO, MONICA; REAL, SILVINA; SANDOVAL, CLAUDIA; MARIN, OSCAR; COMEDI, DAVID

Ghent

Simposio; 11th International Symposium on Electrokinetics Phenomena ELKIN 2014; 2014

Universiteit Genth

In the present work electrophoretic deposition (EPD) (1), which involves the guided drift and deposition of charged particles in a colloidal suspension under the influence of a suitable electric field, is used to produce ordered ZnO nanowire arrays on silicon substrates, which were covered with Au nano-clusters deposited by sputtering (2) at room temperature.The ZnO nanostructures were grown from a low concentration colloidal suspension of ZnO na-noparticles in 2-propanol (3). The size of the nanoparticles obtained in the colloidal suspension was estimated from absorbance and photoluminescence measurements (4, 5), which yielded an average diameter of 5 nm with a narrow size distribution. Physical and chemical properties of the resulting colloidal suspension were measured, such as conductivity, pH, zeta potential, densi-ty, and viscosity, in order to calculate relevant parameters for the EPD technique.A careful design of the EPD cell was performed in order to find the best way to obtain homoge-neous and reproducible deposits. This allowed the engineering of the directionality and intensity of the applied electric field, which is one of the main parameters determining the effectiveness of the EPD method in producing complex nanostructures with controlled thickness and mor-phology. The effect of process parameters on the obtained nanostructures properties such as deposition time, intensity and distribution of the electric field, as well as the addition of different zinc nitrate concentrations to the colloidal suspensions, were studied and discussed.Scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy, and photolumines-cence measurements were performed in order to determine the quality of the ZnO nanostruc-tures obtained by EPD.The growth of ZnO semiconductor nanowires is of great industrial interest because ZnO is a wide band gap (3.37 eV) n-type semiconductor with photoconductive properties and high exci-tonic binding energy, which make it potentially useful for the design of photonic devices, such as UV photo detectors, solar cells, laser and optical memories. ZnO nanostructures have also been proposed as suitable nanomaterials for sensors, actuators and nano-enabled synthetic biol-ogy [6].References 1.R. Monero, B. Ferrari, Electrophoretic Deposition of Nanomaterials, Chapter 2, Springer 2012, 73-128. Eds. J.H. Dickerson and A.R. Boccaccini2.N.C. Vega, R. Wallar, J. Caram, G. Grinblat, M. Tirado, R.R. LaPierre, D. Comedi, Nanotechnology 2012, 23, 2756023.D.W. Bahnemann, C. Kormann, M.R. Hoffmann, J. Phys. Chem. 1987, 91, 37894.L.E. Brus, J. Chem. Phys. 1984, 80, 44035.N.S. Pesika, et al, Journal of Phys. Chem. B 2003 107(38), 104126.T.J. Athauda, P. Hari, R.R. Ozer, ACS Appl. Mater. Interfaces 2013, 5, 6237