Direct Measurement of Band Edge Profiles at Epitaxial Oxide/Semiconductor Heterojunctions

ORAL

Abstract

Band edge profiles for semiconductor heterojunctions can be approximated using transport data and/or calculated from first principles, assuming an atomistic materials structure. However, direct and accurate experimental measurement has not been possible by traditional means. We have used hard x-ray photoelectron spectroscopy (HAXPES) to extract band edge profiles from core-level spectra by developing an effective algorithm that fits experimental heterostructure spectra to sums of flat-band spectra, measured for pure reference materials, in which the binding energies are exhaustively varied to sample the phase space of physically reasonable potential profiles over all layers within the HAXPES probe depth. We apply this method to heterojunctions of n-SrNbxTi1-xO3 and intrinsic Si(001), prepared by molecular beam epitaxy. Heterojunction formation results in a Si hole gas and a surface depleted dead layer in the SrNbxTi1-xO3. The band edge profiles resulting from the HAXPES fitting reveal both of these features, and match what is expected based on Hall data remarkably well. In this talk, we present highlights of this analysis.

*This work was supported by the U.S. Department of Energy, Office of Science, Division of Materials Sciences and Engineering under Award #10122.

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Presenters

  • Scott Chambers

    • Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory
    • Physical Sciences Division, Pacific Northwest National Laboratory
    • Pacific Northwest Natl Lab

Authors

  • Scott Chambers

    • Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory
    • Physical Sciences Division, Pacific Northwest National Laboratory
    • Pacific Northwest Natl Lab

  • Petr Sushko

    • Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory
    • Pacific Northwest Natl Lab

  • Nicholas F Quackenbush

    • Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology
    • Materials Measurement Science Division, National Institute of Standards
    • Materials Measurement Science Division, National Institute of Standards and Technology

  • Joseph Woicik

    • Materials Measurement Science Division, National Institute of Standards
    • Materials Measurement Science Division, National Institute of Standards and Technology
    • Ceramics Division, National Institute of Standards and Technology

  • Zheng Hui Lim

    • Department of Physics, University of Texas at Arlington
    • Department of Physics, University of Texas-Arlington

  • Matthew Chrysler

    • Department of Physics, University of Texas at Arlington
    • Department of Physics, University of Texas-Arlington

  • Joseph Ngai

    • Department of Physics, University of Texas at Arlington
    • Department of Physics, University of Texas-Arlington

  • Tien-Lin Lee

    • Diamond Light Source
    • Diamond Light Source, UK

  • James Ablett

    • Synchrotron SOLEIL

  • mark bowden

    • Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory
    • Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory
    • Pacific Northwest Natl Lab

  • Zihua Zhu

    • Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory
    • Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory

  • Aubrey Penn

    • Department of Materials Science & Engineering, North Carolina State University

  • James LeBeau

    • Department of Materials Science & Engineering, North Carolina State University