Adsorption-controlled growth of BiMnO3 films by molecular-beam epitaxy.

We have developed the means to grow BiMnO₃ thin films with unparalleled structural perfection by reactive molecular-beam epitaxy and determined its band gap. Film growth occurs in an adsorption-controlled growth regime. Within this growth window bounded by oxygen pressure and substrate temperature at a fixed bismuth overpressure, single-phase films of the metastable perovskite BiMnO₃ may be grown by epitaxial stabilization. X-ray diffraction reveals phase-pure and epitaxial films with ω rocking curve full width at half maximum values as narrow as 11 arc sec (0.003°). Optical absorption measurements reveal that BiMnO₃ has a direct band gap of 1.1±0.1 eV. [ABSTRACT FROM AUTHOR]