Mapping hidden space-charge distributions across crystalline metal oxide/group IV semiconductor interfaces

ORAL

Abstract

Dopant profiles in semiconducting heterojunctions can have major effects on band energies which in turn drive transport properties. Here we use core-level photoelectron line shapes excited with hard x-rays to extract information about electric fields resulting from internal charge transfer in epitaxial La-doped Sr(Ti,Zr)O3/Ge(001) heterostructures. Experiments were carried out using both n- and p-type Ge substrates. These heterojunctions were not amenable to electronic characterization of all regions by transport measurements because the doped substrates act as electrical shunts, precluding probing the more resistive films and masking interface conductivity. However, the core-level line shapes were found to be a rich source of information on built-in potentials that exist throughout the heterostructure and yielded valuable insight into the impact of band bending on band alignment at the buried interfaces. The electronic effects expected for Ge with uniform n- and p-type doping are eclipsed by those of unintended oxygen dopants in the Ge near the interface. This study illustrates the power of hard x-ray photoemission spectroscopy and related modeling to determine electronic structure in material systems for which insight from traditional transport measurements is limited.

*This work was supported by the National Science Foundation (DMR-1508530) and the U.S. Department of Energy, Office of Science, Division of Materials Sciences and Engineering (Award #10122). Diamond Light Source is acknowledged for time on beamline I09 under proposal SI25582.

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Publication: Submitted to Physical Review Materials

Presenters

  • Scott Chambers

    • Pacific Northwest Natl Lab
    • Physical Sciences Division, Physical & Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA

Authors

  • Scott Chambers

    • Pacific Northwest Natl Lab
    • Physical Sciences Division, Physical & Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA

  • Matthew Chrysler

    • University of Texas at Arlington

  • Joseph Ngai

    • University of Texas at Arlington

  • Tien-Lin Lee

    • Diamond Light Source
    • Diamond Light Source, Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
    • Diamong Light Source

  • Judith Gabel

    • 2Diamond Light Source, Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
    • Diamond Light Source

  • Steven Spurgeon

    • Pacific Northwest National Laboratory
    • Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA

  • Bethany Matthews

    • Pacific Northwest National Laboratory
    • Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA

  • Mark Bowden

    • Pacific Northwest National Laboratory

  • Zihua Zhu

    • Environmental Molecular Sciences Laboratory, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
    • Pacific Northwest National Laboratory

  • Peter Sushko

    • Physical Sciences Division, Physical & Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
    • Pacific Northwest National Laboratory