OPTICAL SPECTROSCOPY OF OPAL MATRICES WITH CDS EMBEDDED IN ITS PORES - QUANTUM CONFINEMENT AND PHOTONIC BAND-GAP EFFECTS

The spectra of transmission and reflection of synthetic opal which has 3-dimensional periodic structure were measured at different orientati ons of incident beam relative to the sample facets. It is shown that o pal behaves as ''semi-metallic'' photonic band gap (PBG) material in t he vicinity of photon energy 2.3 eV. The synthesis of CdS microcrystal s embedded in the pores of opal was made for the first time in an atte mpt to form a system of quantum dots. Optical spectra (reflection and transmission, photoluminescence and Raman scattering) were studied. Th e results demonstrate good crystallinity of microcrystals embedded in opal matrix and exhibit well-pronounced quantum confinement effects in fundamental edge absorption spectra. The spectral overlap of the PBG of opal with electronic band gap of many of II-VI semiconductors seems to make opal/semiconductor system a promising media for experimental studies of such PBG-related effects as inhibition of spontaneous emiss ion, microcavity polariton, etc.