Optical properties of CdSe and CdTe nanoparticles embedded in SiO2 films

Abstract

ABSTRACTCdSe and CdTe nanoparticles dispersed in silicon dioxide films have been grown by magnetron sputtering technique followed by thermal annealing. Effect of thermal annealing conditions on the structural and optical properties of CdTe and CdSe nanoparticles has been studied. Glancing angle x-ray diffraction (GAXRD), optical absorption (OA), transmission electron microscope (TEM) and spectroscopic ellipsometry (SE) techniques have been used to study the crystal structure, particle size and dielectric function spectra of nanoparticles. ε2 spectra of CdTe nanoparticles show a decrease in dielectric constant values in comparison to bulk CdTe. ε2″ spectrum of CdTe nanoparticles show four critical points in the electronic band structure of CdTe. Optical absorption studies in the case of CdTe and CdSe nanoparticles clearly show the blue shift of fundamental absorption edge due to quantum confinement effect.