Influenza of the Cu Ion on the Structural and Optical Properties in Cu + Ce Co-Doped ZnO Compounds

Abstract

This article showed and explained the effects of the Cu 2+ ions on the structural and photoluminescent properties of Ce 3+ doped ZnO compounds (ZnO: Ce 3+ ) in Cu 2+ + Ce 3+ co-doped ZnO (ZnO: Cu 2+ + Ce 3+ ) solid solutions powders. The samples were synthesized by a solution combustion method maintaining the Ce 3+ ion concentration constant in 3%wt and varying the Cu 2+ ion concentration in 0%wt, 1%wt, 2%wt, 3%wt, 10%wt and 20%wt. However, pristine ZnO and Ce 3+ doped ZnO were synthesized by the same method for comparison. After the synthesis process all the samples were annealed at 900°C by 24 h. The pure ZnO, ZnO: Ce 3+ and ZnO/Cu 2+ + Ce 3 powders were structurally characterized using X-ray diffraction (XRD) technique, the XRD patterns showed that for either undoped and doped with the Cu 2+ ion both exhibited the hexagonal wurtzite ZnO crystalline structure, also the diffraction peaks of both samples types showed a little change toward lesser angles. The morphology and particle size of the samples were observed by means of a scanner electron microscopy (SEM); from SEM imagen is observed that the crystallites of the samples are agglomerated forming cage-like hollow structures caused by the combustion process. The cage-like structures have approximate size of 800 nm. In addition, the photoluminescence of pure ZnO, ZnO: Ce 3+ and ZnO: Cu 2+ + Ce 3+ compounds was measurement as a function of Cu 2+ ion concentration under a excitation wavelength of 378 nm in the UV region. As an important result, it is observed that by Auger phenomena of non-radiative recombination, the UV emission of the ZnO is quenching.