Desorption of Hydrogen from Si(111) by Resonant Excitation of the Si-H Vibrational Stretch Mode

ORAL

Abstract

We report first measurements of non-thermal, non-electronic resonant photodesorption of hydrogen from a Si(111) surface using tunable infrared radiation. The wavelength dependence of the desorption yield Shows a peak at 0.26 eV, the energy of the Si-H vibrational stretch mode. The corresponding excitation cross section is determined to be $2.3\times10^{-18}$ cm$^2$. The desorption yield is quadratic in the infrared intensity and quartic in the electric field along the Si-H bond direction. We postulate that two neighboring hydrogen adatoms, once simultaneously excited in their vibrational stretch mode, can desorb associatively at room temperature.

*This work is funded by DARPA/SPAWAR grant N66001-04-1-8924, DOE grant ER45781 and NSFgrant DMR-0306239.

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Authors

  • Zhiheng Liu

    • University of Minnesota

  • Leonard Feldman

    • Department of Physics and Astronomy \& Interdisciplinary Materials Science Program, Vanderbilt University
    • Vanderbilt University
    • Department of Physics and Astronomy, Vanderbilt University
    • Department of Physics and Astronomy \& Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37235

  • Norman Tolk

    • Department of Physics and Astronomy, Vanderbilt University
    • Vanderbilt University

  • Zhenyu Zhang

    • Condensed Matter Sciences Division, Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • Oak Ridge National Laboratory \& University of Tennessee
    • University of Tennessee \& ORNL
    • Oak Ridge National Lab
    • Oak Ridge National Lab, University of Tennessee

  • Philip Cohen

    • University of Minnesota