Polymorph‐Tuned Synthesis of α‐ and β‐Bi2O3 Nanowires and Determination of Their Growth Direction from Polarized Raman Single Nanowire Microscopy

Abstract We report polymorph‐tuned synthesis of α‐ and β‐Bi 2 O 3 nanowires and their single nanowire micro‐Raman study. The single crystalline Bi 2 O 3 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 Bi 2 O 3 nanowires were simultaneously synthesized along the temperature gradient at a substrate. The growth direction of α‐Bi 2 O 3 nanowires was revealed by polarized Raman single nanowire spectra. For thin β‐Bi 2 O 3 nanowires with a very small diameter, the polarized Raman single nanowire spectrum was strongly influenced by the shape effect.