Structural characterization of BaSnO3 thin films via x-ray scattering

The alkaline earth stannate BaSnO3 is a semiconductor with high carrier mobility at room-temperature when doped with La3+. BaSnO3 can be easily integrated with other perovskites for use in oxide electronic devices such as field effect transistors and sensors. We study the crystalline structure of BaSnO3 thin films grown on SrTiO3 substrates by pulsed laser deposition and molecular beam epitaxy via a variety of x-ray scattering techniques. With high intensity synchrotron scattering, we measure crystal truncation rods. Analysis of these rods yields information on structural distortions at the thin film surface and interface. We also measure rocking curves of BaSnO3 fundamental Bragg peaks for H+K+L=even and odd, where the intensity of the odd peaks are particularly sensitive to minute structural changes in the BaSnO3 film. These measurements have high accuracy, with a coefficient of variation within 5 percent for symmetrically identical peaks in the four quadrants of reciprocal space. We fit the integrated intensity of these fundamental even and odd peaks to a kinematic model of x-ray diffraction and determine parameters, including the Debye-Waller factor and the stoichiometry.