High quality SrBi2Nb2O9 ferroelectric thin films were fabricated on platinized silicon using pulsed laser deposition assisted with dc glow discharge plasma. Microstructure and ferroelectric properties of the films were characterized. Optical properties of the thin films were studied by spectroscopic ellipsometry and photoluminescence from the ultraviolet to the infrared region. Optical constants, n~0.56 in the infrared region and n~2.24 in the visible spectral region, were determined through multilayer analyses on their respective pseudodielectric functions. The band-gap energy is estimated to be 3.60 eV. A photoluminescence peak at 0.78 µm, whose intensity decreases with decreasing temperature, was observed when excited with subband-gap energy (2.41 eV). This emission process may involve intermediate defect states at the crystallite boundaries. A possible mechanism for the observed photoluminescence, a Nb4+-O- exciton in the NbO6 octahedron, is discussed.
P. Yang et al., "Growth and Optical Properties of SrBi₂Nb₂O₉ Ferroelectric Thin Films Using Pulsed Laser Deposition," Journal of Applied Physics, American Institute of Physics (AIP), Jun 2003.
The definitive version is available at http://dx.doi.org/10.1063/1.1571219
Mechanical and Aerospace Engineering
Keywords and Phrases
Bismuth Compounds; Dielectric Function; Ellipsometry; Energy Gap; Ferroelectric Thin Films; Optical Constants; Photoluminescence; Plasma Deposited Coatings; Pulsed Laser Deposition; Strontium Compounds
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