title: Ultrafast vibrational dynamics and stability of deuterated amorphous silicon.
abstract: Infrared four-wave mixing experiments performed upon deuterated amorphous silicon layers (a-Si:D) reveal profound differences in the dynamics of Si-D stretch vibrations compared to those of analogous Si-H vibrational modes in hydrogenated amorphous silicon (a-Si:H). Remarkably, transient-grating measurements of the population decay rate of the Si-D vibrations show single-exponential decay directly into collective modes of the a-Si host, bypassing the local bending modes of the defect into which the Si-H vibrations decay. Photon-echo measurements of the vibrational dephasing suggest at low temperature contributions from TO nonequilibrium phonons and at elevated temperatures elastic phonon scattering of TA phonons.
authors.affiliation: Felix Free Electron Laser Facility, FOM-Institute for Plasmaphysics "Rijnhuizen," P.O. Box 1207, 3430 BE, Nieuwegein, The Netherlands.
authors.forename: Jon-Paul R
authors.initials: JP
authors.lastname: Wells
authors.forename: Ruud E I
authors.initials: RE
authors.lastname: Schropp
authors.forename: Lex F G
authors.initials: LF
authors.lastname: van der Meer
authors.forename: Jaap I
authors.initials: JI
authors.lastname: Dijkhuis