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 degrees C was mainly controlled via a vapor-liquid-solid process, whereas the growth at 800 degrees C was dominated by a vapor-solid mechanism. Although 600 degrees 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 degrees C-grown nanowires, both the stem and tip were mainly comprised of cubic Bi-4(GeO4)(3) phase with additional Bi2O3 and GeO2 phases. Photoluminescence spectrum of 800 degrees 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.