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.

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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