Target stoichiometry and growth temperature impact on properties of BiVO 4 (010) epitaxial thin films

• Published in: CrystEngComm 2018-11, Vol.20 (43), p.6950-6956
• Main Authors: Li, Guoqiang, Kou, Shiwen, Zhang, Feng, Zhang, Weifeng, Guo, Haizhong
• Format: Article
• Language: English
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/C8CE01246F

The effects of target stoichiometry and growth conditions on the structure and properties of the monoclinic bismuth vanadate (BiVO 4 ) (010) epitaxial films created using pulsed laser deposition were studied systematically. It is shown that phase-pure monoclinic BiVO 4 epitaxial films were fabricated from a nonstoichiometric target with a bismuth/vanadium (Bi : V) ratio of 6 at 680 °C. The three-dimensional and adsorption-controlled growth process was confirmed using X-ray diffraction and atomic force microscopy. The valence states of Bi 3+ and V 5+ were determined from the results of X-ray photoelectron spectroscopy (XPS), indicating that the BiVO 4 film has substantial stoichiometry. The results of the valence band XPS indicated that the Bi 6s energy level of the BiVO 4 (010) film was located much deeper than that of the polycrystalline sample. The direct optical band gap of the BiVO 4 film was found to be 2.59 eV. The photocatalytic oxidization activity of the single crystal BiVO 4 film for rhodamine B degradation is about one order of magnitude higher in comparison with the polycrystalline sample, indicating that the nanostructured BiVO 4 film is a promising material for obtaining better photocatalytic activity.