Band gap structure modification of amorphous anodic Al oxide film by Ti-alloying

Stela Canulescu, K. Rechendorff, C. N. Borca, N. C. Jones, Kirill Bordo, Jørgen Schou, Lars Pleth Nielsen, S. V. Hoffmann, Rajan Ambat

    Research output: Contribution to journalJournal articleResearchpeer-review

    1317 Downloads (Orbit)

    Abstract

    The band structure of pure and Ti-alloyed anodic aluminum oxide has been examined as a function of Ti concentration varying from 2 to 20 at. %. The band gap energy of Ti-alloyed anodic Al oxide decreases with increasing Ti concentration. X-ray absorption spectroscopy reveals that Ti atoms are not located in a TiO2 unit in the oxide layer, but rather in a mixed Ti-Al oxide layer. The optical band gap energy of the anodic oxide layers was determined by vacuum ultraviolet spectroscopy in the energy range from 4.1 to 9.2 eV (300–135 nm). The results indicate that amorphous anodic Al2O3 has a direct band gap of 7.3 eV, which is about ∼1.4 eV lower than its crystalline counterpart (single-crystal Al2O3). Upon Ti-alloying, extra bands appear within the band gap of amorphous Al2O3, mainly caused by Ti 3d orbitals localized at the Ti site.
    Original languageEnglish
    Article number121910
    JournalApplied Physics Letters
    Volume104
    Issue number12
    Number of pages5
    ISSN0003-6951
    DOIs
    Publication statusPublished - 2014

    Fingerprint

    Dive into the research topics of 'Band gap structure modification of amorphous anodic Al oxide film by Ti-alloying'. Together they form a unique fingerprint.

    Cite this