AVS 45th International Symposium
    Surface Science Division Tuesday Sessions
       Session SS3-TuA

Paper SS3-TuA6
Photodesorption of Atomic Hydrogen from Si(100) at 157 nm

Tuesday, November 3, 1998, 3:40 pm, Room 314/315

Session: Photon- and Electron-Induced Chemistry
Presenter: X.-Y. Zhu, University of Minnesota
Authors: X.-Y. Zhu, University of Minnesota
T. Vondrak, University of Minnesota
Correspondent: Click to Email
Irradiation of the Si(100)-(2x1):H monohydride surface by 157 nm light results in the breaking of the H-Si surface bond and the desorption of atomic hydrogen. This process can be attributed to the resonant photo-excitation of the sigma-sigma* transition of H-Si at the photon energy of 8 eV. The photodesorption cross section is 3 x 10@super -21@ cm@super 2@, independent of surface hydrogen coverage. Time-of-flight (TOF) measurement of the photodesorbed atomic hydrogen yields a mean translational energy of = 74 meV. Such a low translational energy is indicative of the short lived electronic excitation on the semiconductor surface. This short-time dynamic process is further explored by wavepacket simulation on ab initio potential energy surfaces.