Impact of oxygen source parameters on homoepitaxial ZnO films grown at low-temperature on Zn-polar substrates

    Authors

    M. Wei; R. C. Boutwell; G. A. Garrett; K. Goodman; P. Rotella; M. Wraback;W. V. Schoenfeld

    Comments

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    Abbreviated Journal Title

    J. Alloy. Compd.

    Keywords

    ZnO; Molecular beam epitaxy; Homoepitaxy; Oxygen plasma; Atomic force; microscopy; MOLECULAR-BEAM EPITAXY; PLASMA; CRYSTAL; Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy &; Metallurgical Engineering

    Abstract

    ZnO thin films were epitaxially grown on Zn-polar (0001) ZnO substrates by plasma-assisted molecular beam epitaxy at a low temperature of 610 degrees C. The influence of Zn/O ratio on the epitaxial growth of ZnO was investigated. By optimizing the Zn/O ratio, a surface root mean square roughness of 0.277 nm with one or two monolayer height steps was achieved at a low growth temperature by growing on ZnO substrates with 0.5 degrees miscut angle toward the [1 (1) over bar 00] axis. Electrostatic ion trapping of the oxygen plasma was found crucial to deflect etching oxygen species at an oxygen flow rate of two standard cubic centimeters per minute, resulting in fewer surface defects and a longer photoluminescence (PL) lifetime of 217 ps. The impact of oxygen source gas purity was studied by high resolution X-ray diffraction and time-resolved photoluminescence (TRPL) measurements of resultant epilayers and higher gas purity was found necessary to reduce non-radiative centers. (C) 2012 Elsevier B. V. All rights reserved.

    Journal Title

    Journal of Alloys and Compounds

    Volume

    552

    Publication Date

    1-1-2013

    Document Type

    Article

    Language

    English

    First Page

    127

    Last Page

    130

    WOS Identifier

    WOS:000313653300022

    ISSN

    0925-8388

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