Temperature-controlled synthesis and characterization of Bi4Ge3O12 nanowires

Abstract

Varying the heating temperature of a mixture of Bi and Ge powders, we have successfully prepared Bi4Ge3O12 nanowires. The growth at 600 °C was mainly controlled via a vapor?liquid?solid process, whereas the growth at 800 °C was dominated by a vapor?solid mechanism. Although 600 °C-grown nanowires were amorphous, being comprised of Bi, Ge, O, and Au elements, the Bi and Au elements prevalently resided in the tip, playing a catalytic role in the nanowire growth. For 800 °C-grown nanowires, both the stem and tip were mainly comprised of cubic Bi4(GeO4)3 phase with additional Bi2O3 and GeO2 phases. Photoluminescence spectrum of 800 °C-grown nanowires exhibited GeO2-related emission band, as well as Bi4Ge3O12-related ones. The magnetic measurements showed that the Bi4Ge3O12 nanowires exhibited a hysteresis loop, indicating ferromagnetic behavior.