Evidences of the evolution from solid solution to surface segregation in Ni-doped SnO2 nanoparticles using Raman spectroscopy
Article first published online: 27 SEP 2010
Copyright © 2010 John Wiley & Sons, Ltd.
Journal of Raman Spectroscopy
Volume 42, Issue 5, pages 1081–1086, May 2011
How to Cite
Aragón, F. H., Coaquira, J. A. H., Hidalgo, P., da Silva, S. W., Brito, S. L. M., Gouvêa, D. and Morais, P. C. (2011), Evidences of the evolution from solid solution to surface segregation in Ni-doped SnO2 nanoparticles using Raman spectroscopy. J. Raman Spectrosc., 42: 1081–1086. doi: 10.1002/jrs.2802
- Issue published online: 20 MAY 2011
- Article first published online: 27 SEP 2010
- Manuscript Accepted: 14 AUG 2010
- Manuscript Received: 23 JUN 2010
- Ni-doped SnO2 nanoparticles;
- oxide-diluted magnetic semiconductors;
- Raman spectroscopy
Ni-doped SnO2 nanoparticles, promising for gas-sensing applications, have been synthesized by a polymer precursor method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) data analyses indicate the exclusive formation of nanosized particles with rutile-type phase (tetragonal SnO2) for Ni contents below 10 mol%. The mean crystallite size shows a progressive reduction with the Ni content. Room-temperature Raman spectra of Ni-doped SnO2 nanoparticles show the presence of Raman active modes and modes activated by size effects. From the evolution of the A1g mode with the Ni content, a solubility limit at ∼2 mol% was estimated. Below that content, Raman results are consistent with the occurrence of solid solution (ss) and surface segregation (seg.) of Ni ions. Above ∼2 mol% Ni, the redshift of A1g mode suggests that the surface segregation of Ni ions takes place. Disorder-activated bands were determined and their integrated intensity evolution with the Ni content suggest that the solid-solution regime favors the increase of disorder; meanwhile, that disorder becomes weaker as the Ni content is increased. Copyright © 2010 John Wiley & Sons, Ltd.