Synchrotron x-ray scattering study of SnO 2 thin film grown on sapphire

From synchrotron x-ray scattering measurements, it was found that epitaxially grown SnO 2 film on sapphire has a variant structure with threefold symmetry with respect to the substrate and that the ultrathin interfacial layer is formed due to the lattice mismatch between SnO 2 and Al 2 O 3 . The physical properties of the top surface, such as surface morphology, height profile, and roughness, were determined by atomic force microscopy. The height profiles of the film grown at 600 °C and room temperature revealed the asymmetrical and the ordinary symmetric Gaussian distributions, respectively. The difference originates from the dominant diffusion process at high substrate temperature.