Figure 4
Crystal structure of β-Bi2O3 thin films.
(a) X-ray diffraction pattern of a Bi2O3 thin film deposited on a borosilicate glass substrate (synchrotron radiation, λ = 0.95 Å). Measurements were carried out at different sample angles in order to bring into diffraction the maximum number of planes of the film. The results are superimposed in a unique pattern and identified with different colors. A first estimation of its lattice parameters is shown. Diagram at the bottom correspond to the pattern of the β-Bi2O3 phase calculated with the PowerCell program34. (b) Sum of XRD patterns (Cu anode, λ = 1.5406 Å) obtained at different sample orientations (grid of 5° × 5° in χ and φ) for the same Bi2O3 thin film on a borosilicate glass substrate and (c) for another film deposited on a Pt-coated Si substrate. Rietveld refinements (red solid line) reveals that the best fitting is obtained for the tetragonal β-Bi2O3 polymorph. Cell parameters and crystallite sizes are calculated for both films. Diagrams at the bottom of (b and c) correspond to the difference between the experimental and calculated patterns. The goodness of fit (GoF) is included.
