Synthetic Metals 158 (2008) 684–687 Contents lists available at ScienceDirect Synthetic Metals journal homepage: www.elsevier.com/locate/synmet Synthesis and characterization of aligned SiO 2 nanosphere arrays: Spray method G. Gnana Kumar a , S. Senthilarasu b , Dae Nyung Lee a , Ae Rhan Kim a , Pil Kim a,c , Kee Suk Nahm a,c,∗ , Soo-Hyoung Lee b , R. Nimma Elizabeth d a Specialized Graduate School of Hydrogen and Fuel Cell Engineering, Chonbuk National University, Jeonju 561-756, Republic of Korea b School of Semiconductor and Chemical Engineering, Chonbuk National University, Jeonju 561-756, Republic of Korea c School of Chemical Engineering and Technology, Chonbuk National University, Jeonju 561-756, Republic of Korea d Department of Physics, Lady Doak College, Madurai 625002, India article info Article history: Received 12 February 2008 Received in revised form 25 March 2008 Accepted 18 April 2008 Available online 18 June 2008 Keywords: Nanometer Silica Spray Thermal abstract The power of nanomaterials has been hampered by the difficulty in controlling their size and morphol- ogy. Monodispersed silica particles with different nanometer sizes synthesized by a novel spray method remove the obstacles for the commercialization of nanomaterials at a global level. The size and shape of the silica particles were effectively controlled by simple hydrolysis and condensation reaction. Morphological images (SEM and TEM) reveal the smooth and spherical shaped silica particles with homogeneous distri- bution. Structural and luminescence properties of the silica particles were examined by FT-IR absorption spectroscopy and photoluminescence. A very low weight percentile loss of the silica particle ensures its high thermal stability. The high surface areas of about 55 and 25 m 2 /g were achieved for 90 and 220 nm particle sized silica particles, respectively. The resultant silica particles can be easily suspended in water and would be useful for variety of applications. © 2008 Elsevier B.V. All rights reserved. 1. Introduction One-dimensional (1D) nanomaterials such as wires or rods, belts, tubes and cables have attracted tremendous attention due to their importance in basic scientific research and their unique applications in nanoscale devices [1–5]. In particular, 1D silicon oxide nanomaterials are good candidates for photoluminescent, biocompatible materials and their surfaces are accessible to be modified specifically. Therefore, they can often find applications in the areas of nanoscale electronic devices, photographic emulsions, catalysis, pigments, ceramics and the protection of environmen- tally sensitive materials, etc. [6–8]. To date, several methods have been applied to produce silicon oxide nanoparticles, including laser ablation, sol–gel, carbon thermal reduction, and chemical vapor deposition (CVD) [9–13]. However, these previous reports only pro- duced undesirably sparsely populated, randomly oriented silicon oxide particles, resulting in difficulties in direct integration of the nanoparticles into the nanoscale devices. Outstanding collective behaviors can be achieved only by the highly oriented nanosized arrays [14], which will make them promising for many applications. ∗ Corresponding author. Fax: +82 63 270 2306. E-mail address: nahmks@chonbuk.ac.kr (K.S. Nahm). To our best knowledge, the direct fabrication of highly oriented, large-scale of silicon oxide nanoparticle arrays with a controlled morphology still remains a significant challenge. On the other hand, it is vital to elucidate the underlying growth mechanisms that deter- mine the morphology and dimensionality of the 1D nanostructure arrays. Specifically, despite over 40 years of investigations, many characteristics of the well-known vapor liquid–solid (VLS) growth [15] are still not well understood. For example, in the conventional picture of the VLS growth, the prevalent views assume that each of the catalyst alloyed particles will keep the fixed morphology and direct just one piece of nanoparticle growth during the whole growth process. There also claims exist that larger alloyed cata- lyst particles are generally unfavorable for the relevant catalyzed growth of nanoparticles owning to their shape fluctuations [16]. Through spray technique from our protocol, one might gain some new insights into the growth mechanism as well as better control over the nanoparticle size and shape. Hence, an attempt was made on synthesis and characterization of different particle sizes of SiO 2 by spray technique and the results are described. 2. Experimental Tetra ethyl orthosilicate [Si(OC 2 H 5 ) 4 ], distilled water, ammo- nium hydroxide (as a catalyst) and ethanol were used as source 0379-6779/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.synthmet.2008.04.031