Raman Scattering in Nanocomposites Based on Synthetic Opal and Nanocrystalline Bi2TeO5

Resumo

This paper presents a systematic Raman scattering study of novel nanostructured materials based on synthetic opal and Bi₂TeO₅ nanocrystals, which offer high photorefractive sensitivity. Bismuth tellurite was introduced into opal pores in a molten state. The crystal structure of the material in the opal pores was determined by Raman spectroscopy. Comparison of the measured Raman spectra of the opal–Bi₂TeO₅ nanocomposite and those of polycrystalline powders and single crystals made it possible to reveal a number of new bands and analyze their origin. The observed variation in the intensity of Raman bands from point to point on the sample surface can be interpreted as due to structural light focusing and excitation field localization at surface and volume defects of the photonic crystal structure of the material.