Formation and characterization of SnO2 nanobaskets

This work describes the formation and characterization of a novel nanostructured SnO2 film. We have found that RF-magnetron sputtering of SnO2 onto a porous alumina substrate leads to the formation of short, capped nanotubes, termed "nanobaskets". They have been characterized using scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, Raman spectroscopy, and a.c. impedance spectroscopy. Raman spectroscopy shows that vibrational modes associated with this nanostructured SnO2 are considerably different than crystalline SnO2 and indicate that the nanobaskets are composed of smaller nanoparticles less than 4 nm in size. AC impedance data confirm these results by showing a very large grain boundary component that almost completely obscures the contribution of the bulk grains. The nanobaskets can be made with a variety of materials and size ranges, and may be formed in layers of more than one material. (c) 2006 Elsevier B.V. All rights reserved.