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Analysis of Au-Al thin films for application in surface plasmon resonance sensing devices

POSTER

Abstract

Surface plasmon resonance (SPR)-based sensing devices commonly use Au due to its robust, well-defined SPR response. Such devices aim to detect small changes in the index of refraction of a medium and thus rely on materials exhibiting a sharp, well-defined resonance dip in their reflection spectrum. The resonance dip of Au loses definition at high temperatures, making it ill-suited to application in high-temperature sensing devices. In this work, we study the SPR response of thin films of various alloys of Au and Al fabricated using the co-sputtering deposition method and characterize their optical response over a wide range of temperatures (from 25 to 200 ${^\circ}$C). We quantify three figures of merit in sensing applications: the sensitivity of the dip's location in the reflectance spectra, the full width at half maximum (FWHM) and the height of the reflectance dip. An ideal film exhibits a high sensitivity, small FWHM, and large peak height. We perform a full analysis of each of these metrics at both fixed incident angle (for wavelength-dependent sensors) and fixed incident wavelength (for angular dependent sensors), for four thicknesses. All alloys outperform their pure counterparts in sensitivity for the wavelength-dependent SPR sensor, with Au$_{\mathrm{.85}}$Au$_{\mathrm{.15}}$ being more sensitive than its pure counterparts in every configuration we examined for both angular and wavelength-dependent SPR sensors and remained relatively comparable to its pure counterparts in terms of FWHM and peak height.

Authors

  • Molly Kate Kreider

    University of Richmond

  • Peter Schauss

    University of Notre Dame, Los Alamos National Laboratory, North Carolina State University, University of Notre dame, Columbia University, Mississippi State Univ, University of Pennsylvania, Carnegie Mellon University, University of Puerto Rico at Humacao, JLAB, MIT, University of Alabama at Birmingham, Florida State University, NHMFL, University College Dublin, Department of Physics, Florida State University; National High Magnetic Field Laboratory, CNR-Instituto Nanoscienze, Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology, Department of Chemistry, Florida State University, University of Alabama at Birmingham, Department of Physics, Birmingham, AL 35294-1170,USA, Department of Chemistry, Virginia Polytechnic Institute and State University, Francis Marion University, University of Richmond, Valdosta State University, University of Pittsburgh, Fermi National Lab, university of minnesota, Univ of Virginia, Joint Quantum Institute, University of Maryland, Georgetown University, IonQ Inc.

  • Peter Schauss

    University of Notre Dame, Los Alamos National Laboratory, North Carolina State University, University of Notre dame, Columbia University, Mississippi State Univ, University of Pennsylvania, Carnegie Mellon University, University of Puerto Rico at Humacao, JLAB, MIT, University of Alabama at Birmingham, Florida State University, NHMFL, University College Dublin, Department of Physics, Florida State University; National High Magnetic Field Laboratory, CNR-Instituto Nanoscienze, Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology, Department of Chemistry, Florida State University, University of Alabama at Birmingham, Department of Physics, Birmingham, AL 35294-1170,USA, Department of Chemistry, Virginia Polytechnic Institute and State University, Francis Marion University, University of Richmond, Valdosta State University, University of Pittsburgh, Fermi National Lab, university of minnesota, Univ of Virginia, Joint Quantum Institute, University of Maryland, Georgetown University, IonQ Inc.

  • Peter Schauss

    University of Notre Dame, Los Alamos National Laboratory, North Carolina State University, University of Notre dame, Columbia University, Mississippi State Univ, University of Pennsylvania, Carnegie Mellon University, University of Puerto Rico at Humacao, JLAB, MIT, University of Alabama at Birmingham, Florida State University, NHMFL, University College Dublin, Department of Physics, Florida State University; National High Magnetic Field Laboratory, CNR-Instituto Nanoscienze, Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology, Department of Chemistry, Florida State University, University of Alabama at Birmingham, Department of Physics, Birmingham, AL 35294-1170,USA, Department of Chemistry, Virginia Polytechnic Institute and State University, Francis Marion University, University of Richmond, Valdosta State University, University of Pittsburgh, Fermi National Lab, university of minnesota, Univ of Virginia, Joint Quantum Institute, University of Maryland, Georgetown University, IonQ Inc.