Structure and Optical Properties of SrBi2Nb2O9 Thin Films Fabricated by Pulsed Laser Deposition

Abstract

SrBi2Nb2O9 (SBN) thin films were prepared on fused quartz substrates at room temperature by pulsed laser deposition. The crystallization behavior and surface morphology were studied at various oxygen pressures by XRD and AFM. The results indicated that the films had polycrystalline structure with a single layered perovskite phase, and exhibited higher crystalline quality, less rough surface morphology, and larger grain size with increasing oxygen pressure. The optical transmittance of the samples was measured in the wavelength range 200-900 nm, and the dispersion relation of refractive indices and wavelength was found to follow the single electron oscillation model. The energy gap of SBN films grown at oxygen pressure of 5 Pa was estimated to be around 3.88 eV by assuming a direct transition between valence and conduction bands.