Surface modification of yttria-stabilized-zirconia thin films under various oxygen partial pressures

• Published in: Thin solid films Vol. 520; no. 17; pp. 5826 - 5831
• Main Authors: Bae, J.S., Park, S.-S., Mun, B.S., Park, S.H., Hwang, E.S., Kim, J., Huh, J., Park, H.J., Kim, J.S., Yun, H.J., Kim, H.G., Jeong, S.Y., Hwang, J., Park, S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30-06-2012; Elsevier
• Subjects: Composition and phase identification; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystal structure; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical band-gap; Oxide thin films; Oxygen enrichment; Partial pressure; Phase transformations; Physics; Spectra; Spectroscopy; Structure and morphology; thickness; Surface and interface electron states; Surface states, band structure, electron density of states; Surface structure; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theory and models of film growth; Thin film structure and morphology; Thin films; X-ray diffraction; X-rays; Yttria stabilized zirconia; Oxide thin films; X-ray diffraction; Spectroscopy; Optical band-gap; Surface structure; Cubic lattices; Valence bands; Chemical analysis; Photonic band gap; Crystal form; Crystal orientation; Polycrystals; Surface treatments; XRD; Phase transitions; Thin films; Energy gap; Optical properties; Chemical composition; Crystal structure; Electronic properties; Tetragonal lattices; Phase transformations; Stabilized zirconia; Monoclinic lattices; Surface composition; Preferred orientation; Electronic structure; Partial pressure; Growth mechanism; Yttrium oxide; Crystal faces; Structural analysis; X-ray photoelectron spectra
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2012.02.049

This report discusses the structural and spectroscopic analysis of yttria-stabilized-zirconia (YSZ) thin films grown on Al2O3(0001) substrates. It is found that the changes of oxygen partial pressure during the growth are closely related to the surface chemical compositions and the surface crystal orientations of the thin films. The presence of oxygen partial pressure produces a polycrystalline structure on the thin film while a preferred orientation of crystal structures is formed under no oxygen partial pressure. Difficulty arises in identifying the structure of the thin films due to the broad characteristics of the x-ray diffraction (XRD) peaks; however, the XRD rocking scan suggests the existence of two lateral domain sizes. The chemical analysis of the thin films from x-ray photoelectron spectroscopy measurements indicates the enrichment of surface yttrium-oxide as the oxygen partial pressure increases. The detailed analysis of valence band spectra also suggests that the thin films undergo a surface structural phase transition, i.e., transforming from a single tetragonal structure to a mixed (cubic+monoclinic) structure. Furthermore, the optical data display the small increments of the band gap as the oxygen partial pressure increases, which reflects the presence of the structural phase transition of the thin films.
► The rocking scan suggests the existence of two lateral domain sizes. ► The XPS indicates the enrichment of surface yttrium-oxide. ► The valence band spectra suggest that the thin films exhibit structure transforms. ► The optical data display the small increments of the band gap. ► This reflects the presence of the structural phase transition of the thin films.