Epitaxial corundum-VTiO3 thin films grown on c-cut sapphire

THIN SOLID FILMS

卷:631

Article

Kramer, Alan¹  Sutter, Eli²  Su, Dong³  Batzill, Matthias¹ 

[1] Univ S Florida, Dept Phys, Tampa, FL 33620 USA

[2] Univ Nebraska Lincoln, Dept Mech & Mat Engn, Lincoln, NE 68588 USA

[3] Brookhaven Natl Lab, Ctr Funct Nanomat, Upton, NY 11973 USA

关键词: Epitaxial oxide films;    Mixed oxides;    Corundum;    Vanadia;    Titania;    X-ray photoemission spectroscopy;    Molecular beam epitaxy;   

DOI  :  10.1016/j.tsf.2017.04.018

来源: Elsevier

【 摘 要 】

Corundum structured VTiO3 has been grown as epitaxial films on c-cut sapphire by laser molecular beam epitaxy. The properties of the film were characterized by reflection high energy electron diffraction, X-ray diffraction, transmission electron microscopy (TEM), and photoemission spectroscopy. All the structural probes clearly indicate the corundum structure of the film. X-ray photoemission spectroscopy (XPS) indicates that V is in a 3 + charge state implying that Ti also should adopt a 3 + charge state in order for the corundum structure to form. However, the Ti-2p XPS, while clearly broadened to the lower binding energy side compared to TiO2, also exhibits a pronounced Ti4+ component. Similarly TEM-electron energy loss spectroscopy indicates amixture of Ti3+ and Ti4+. This is tentatively assigned to a combination of final state effects in XPS measurements and existence of excess (interstitial) oxygen. The valence band spectra show occupation of 3d metal states that resemblemore closely those of Ti2O3 than for V2O3, suggesting that mostly the a(1g) molecular states are occupied. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

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