Polymorph-tuned Synthesis of a- and b-Bi2O3 Nanowires and Determination of Their Growth Direction from Polarized Raman Single Nanowire Microscopy

Abstract

We report polymorph‐tuned synthesis of α‐ and β‐Bi2O3 nanowires and their single nanowire micro‐Raman study. The single crystalline Bi2O3 nanowires in different phases (α and β) were selectively synthesized by adjusting the heating temperature of Bi precursor in a vapor transport process. No catalyst was employed. Furthermore, at an identical precursor evaporation temperature, α‐ and β‐ phase Bi2O3 nanowires were simultaneously synthesized along the temperature gradient at a substrate. The growth direction of α‐Bi2O3 nanowires was revealed by polarized Raman single nanowire spectra. For thin β‐Bi2O3 nanowires with a very small diameter, the polarized Raman single nanowire spectrum was strongly influenced by the shape effect.