Controlling and quantifying two-level systems via growth parameters in vapor deposited amorphous silicon thin films

ORAL

Abstract

The structure of electron beam evaporated amorphous silicon is shown to depend strongly upon deposition temperature (from 25 to 425 °C) and total film thickness (from 10 to 300 nm), as well as deposition rate (from 0.05 to 2.5 Å/s). Previous work has hypothesized that the occurrence of structural defects is directly related to the increase of two-level systems. Structural qualities are measured by Rutherford BackScattering, Raman spectroscopy, Doppler Broadening Spectroscopy, and Fluctuation Electron Microscopy, whereas two-level systems are determined by specific heat and internal friction measurements. We show that defects are tuned via growth parameters and intrinsically related to two-level systems. Thicker and higher growth temperature films yields lower defects and thus, a lower density of two-level systems. Correlation between structural and energetic qualities suggests the structural motifs where two-level systems are likely to be formed.

*We thank the NSF DMR-1508828 and the Office of Naval Research for support.

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Presenters

  • Manel Molina Ruiz

    • University of California at Berkeley

Authors

  • Manel Molina Ruiz

    • University of California at Berkeley

  • Hilary Jacks

    • University of California at Berkeley

  • David Castells-Graells

    • University of California at Berkeley

  • Daniel Queen

    • NRC Research Associate
    • Northrop Grumman Corp.

  • Mahat Sushant

    • University of Illinois at Urbana-Campaign

  • David Cahill

    • Materials Science and Engineering, University of Illinois at Urbana-Champaign
    • Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign
    • University of Illinois at Urbana-Campaign
    • University of Illinois at Urbana-Champaign
    • University of Illinois at Urbana–Champaign
    • Department of Materials Science and Engineering and Materials Research Laboratory, Univ of Illinois - Urbana
    • Univ of Illinois - Urbana
    • Univ of Illinois at Urbana-Champaign
    • Department of Materials Science and Engineering, University of Illinois

  • Jason Maldonis

    • University of Wisconsin at Madison

  • Paul Voyles

    • University of Wisconsin at Madison

  • Matthew Abernathy

    • Naval Research Lab, NRC Research Associate
    • Naval Research Laboratory
    • NRC Research Associate

  • Thomas Metcalf

    • Naval Research Lab
    • Naval Research Laboratory

  • Xiao Liu

    • Code 7130, Naval Research Lab
    • Naval Research Lab
    • Naval Research Laboratory

  • Marc Weber

    • Washington State University

  • Frances Hellman

    • Univ of California - Berkeley
    • University of California at Berkeley
    • University of California, Berkeley, Department of Physics, and Lawrence Berkeley National Laboratory, Materials Sciences Division