Generation of Zn2SiO4 Nanocrystallites in a Shell of ZnO/SiOx Core-Shell Nanowires to Change Photoluminescence Properties

Abstract

This study addresses the annealing effects of ZnO/SiOx core-shell nanowire optical properties, in terms of Zn2SiO4 crystallite generation. At 700 A degrees C, the integrated PL intensity of deep-level emission was increased by annealing. With regard to UV emission, free exciton (FX) peak intensity was reduced and the ratio of FX to non-FX peak intensities increased as annealing temperature was increased. These annealing induced changes, including the enhancement of deep-level emission and suppression of FX emission, are mainly related to the generation of Zn2SiO4 crystallites. Transmission electron microscopy revealed that Zn2SiO4 crystallites were formed inside the SiOx shell layer.