Influence of the Gas Supply on the Elimination of Impurities and Surface Morphology of δ-Bi<sub>2</sub>O<sub>3</sub> Thin Film under Atmospheric Pressure by Means of Halide CVD on C-Sapphire

This report describes that the influence of the gas supply on the decrease of impurities and surface morphology of δ-Bi2O3 thin film by means of chemical vapor deposition under atmospheric pressure using BiI3 and O2 gas as starting materials. X-ray photoelectron spectroscopy and Energy dispersive X-ray spectrometer analyses revealed the remarkable decrease of impurities from the deposited film when put close to 60 mm against the O2 gas line. By changing growth position, the incorporation of the iodine was completely suppressed. Obtained iodine-free δ-Bi2O3 thin film was not flat than that of the previous report, but also had a rather irregular shape and the average grain size was a few micrometers.