Temperature-controlled synthesis of Zn2GeO4 nanowires in a vapor-liquid-solid mode and their photoluminescence properties

Abstract

Varying the heating temperature of a mixture of Zn and Ge powders, we have successfully prepared Zn2GeO4 nanowires. We suggest that the 900 degrees C-grown product was mainly grown via a vapor-liquid-solid process, whereas the 800 degrees C-grown product was dominated by a vapor-solid mechanism. For 900 degrees C-grown nanowires, the stem is mainly comprised rhombohedral Zn2GeO4 phase, whereas the tip is characterized by a particle hexagonal GeO2 phase. For 800 degrees C-grown nanowires, both the stem and tip are mainly comprised hexagonal ZnO phase with some additional Zn2GeO4 phase. It was observed that variation of the growth temperature affected the photoluminescence spectra of the nanowires, leading to an overall intensification. We have discussed the possible mechanisms for the observed temperature-induced changes in the PL spectra.