Optical band gap of BiFeO3 grown by molecular-beam epitaxy

Authors

• J. F. Ihlefeld, Pennsylvania State University
• N. J. Podraza, Pennsylvania State University
• Z. K. Liu, Pennsylvania State University
• R. C. Rai, University of Tennessee
• X. Xu, University of Nebraska-LincolnFollow
• T. Heeg, Research Centre Julich
• Y. B. Chen, University of Michigan-Ann Arbor
• J. Li, University of Toledo
• R. W. Collins, University of Toledo
• J. L. Musfeldt, University of Tennessee
• X. Q. Pan, University of Michigan-Ann Arbor
• J. Schubert, Research Centre Julich
• R. Ramesh, University of California - Berkeley
• D. G. Schlom, Pennsylvania State UniversityFollow

Document Type

Article

Date of this Version

2008

Citation

Appl. Phys. Lett. 92, 142908 (2008)

Comments

Used by permission.

Abstract

BiFeO₃ thin films have been deposited on (001) SrTiO₃ substrates by adsorption-controlled reactive molecular-beam epitaxy. For a given bismuth overpressure and oxygen activity, single-phase BiFeO₃ films can be grown over a range of deposition temperatures in accordance with thermodynamic calculations. Four-circle x-ray diffraction reveals phase-pure, epitaxial films with w rocking curve full width at half maximum values as narrow as 29 arc sec (0.008°). Multiple-angle spectroscopic ellipsometry reveals a direct optical band gap at 2.74 eV for stoichiometric as well as 5% bismuth-deficient single-phase BiFeO₃ films.