Room temperature photoluminescence of CdTe nanocrystals embedded in a SiO2 matrix deposited on silicon by reactive rf sputtering

Abstract

CdTe nanocrystals embedded in a SiO2 matrix were fabricated by radio frequency sputtering employing the texture of a SiO2 layer as template. The SiO2 film texture was controlled through the O2 partial pressure (OPP) in the working atmosphere. The CdTe crystallinity was better for the samples synthesized on rougher SiO2 films. For these samples, the room temperature photoluminescence spectra showed a signal at 1.74 eV, related to the CdTe nanoparticles. Additional photoluminescence signals at 1.65 and 1.68 eV have been associated to recombination processes at the nanoparticle/matrix interfaces. The results indicate that the employed methodology produces, in a single step, CdTe nanoparticles with light emission at room temperature. After thermal annealing all the samples presented emission due to quantum confinement effects. The photoluminescence emission may be varied from 1.69 to 2.15 eV by appropriate control of the OPP.