Ab initio studies of Al, O, and O2 adsorption on αAl2O3(0001) surfaces

E. Wallin, J. M. Andersson, E. P. Münger, V. Chirita, and U. Helmersson
Phys. Rev. B 74, 125409 – Published 8 September 2006

Abstract

The interactions of Al, O, and O2 with different αAl2O3(0001) surfaces have been studied using ab initio density functional theory methods. All three surface terminations obtainable by cleaving the bulk structure [single Al-layer (AlO), double Al-layer (AlAl), and O terminations] have been considered, as well as a completely hydrogenated O-terminated surface. Adsorbed Al shows strong ioniclike interaction with the AlO- and O-terminated surfaces, and several metastable adsorption sites are identified on the O-terminated surface. On the completely hydrogenated surface, however, Al adsorption in the bulk position is found to be unstable or very weak for the studied configurations of surface H atoms. Atomic O is found to interact strongly with the AlAl-terminated surface, where also O2 dissociative adsorption without any appreciable barrier is observed. In contrast, O adsorption on the AlO-terminated surface is metastable relative to molecular O2. On the O-terminated surface, we find the creation of O surface vacancies to be plausible, especially upon exposure to atomic O at elevated temperatures. The results are mainly discussed in the context of alumina thin film growth and provide insight into phenomena related to, e.g., preferred adsorption sites and effects of hydrogen on the growth.

    • Received 12 July 2006

    DOI:https://doi.org/10.1103/PhysRevB.74.125409

    ©2006 American Physical Society

    Authors & Affiliations

    E. Wallin1,*, J. M. Andersson1, E. P. Münger2, V. Chirita2, and U. Helmersson1

    • 1Plasma & Coatings Physics Division, IFM Material Physics, Linköping University, SE-581 83 Linköping, Sweden
    • 2Theoretical Physics Division, IFM Theory and Modelling, Linköping University, SE-581 83 Linköping, Sweden

    • *Corresponding author. Electronic address: eriwa@ifm.liu.se

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    Issue

    Vol. 74, Iss. 12 — 15 September 2006

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