Formation of bismuth oxide nanostructures by reactive plasma assisted thermal evaporation

• The 3D mixed β-Bi2O3 and δ-Bi2O3 phase nanostructures were deposited.
• Delta-Bi2O3 phase nanowires were grown at 500 °C temperature.
• Amorphous Bi2O3 films were grown at 30 °C and 200 °C temperatures.

Bismuth oxide films and nanostructures were deposited using reactive plasma assisted thermal evaporation. The growth temperature varied in the range of 30–500 °C in order to obtain the single phase Bi2O3. The as-deposited Bi2O3 structures were characterized for their structural, surface morphological and optical properties using X-ray diffraction (XRD), scanning electron microscopy, and optical absorption measurements, respectively. The XRD analyses demonstrated the formation of Bi2O3 films amorphous phases at deposition temperatures below 200 °C. Meanwhile the crystalline phase's (β-Bi2O3 with δ-Bi2O3 or δ-Bi2O3) bismuth oxide nanostructures were formed at higher grown temperatures. The nanostructures were approximately 100–500 nm of length with the diameter of 50–100 nm. The optical band gap of Bi2O3 films and nanostructures varied in the range of 2.75–3.05 eV.