Raman spectroscopic investigations of nanoparticles of Sn(x)Ti(1-x)O2 solid solution

SnO2 nanoparticles dispersed in TiO2 matrix are prepared at a relatively low temperature of approximately 185 degrees C. Nanoparticles of Sn(x)Ti(1-x)O2 solid solution without significant aggregation have been prepared by annealing them at approximately 500 and 900 degrees C. X-ray diffraction and high-resolution transmission electron microscopy studies have clearly established the nano-size nature of the samples. Raman spectroscopic investigations of these samples show mixed vibrational modes, some of them being similar to TiO2 (A(1g), E(g)), while some of them are similar to SnO2 (B(2g)). The E(g) mode shows significant red shift and B(2g) mode shows significant blue shift. Unlike this A(1g) mode remains unaffected. These results are explained based on the combined effects of random alloy formation and the nano-size nature of samples.