| AVS 59th Annual International Symposium and Exhibition | |
| Electronic Materials and Processing | Wednesday Sessions |
| Session EM+TF-WeM |
| Session: | Hybrid Electronic Materials and Interfaces |
| Presenter: | Z.M. Hund, University of Chicago |
| Authors: | Z.M. Hund, University of Chicago R.D. Brown, University of Chicago L.E. O'Leary, California Institute of Technology D. Campi, Universitả di Milano-Bicocca, Italy M. Bernasconi, Universitả di Milano-Bicocca, Italy G. Benedek, Universitả di Milano-Bicocca, Italy N.S. Lewis, California Institute of Technology S.J. Sibener, University of Chicago |
| Correspondent: | Click to Email |
Surface dynamical properties of methyl-terminated silicon(111) were investigated with energy and momentum resolved inelastic helium atom scattering measurements. The narrow energy distribution and nondestructive nature of neutral helium atom beams allow us to probe the vibrational dynamics of this hybrid organic-semiconductor interface. Time-of-flight experiments identify single phonon inelastic scattering events including, but not limited to, those attributed to Rayleigh wave excitations. We have mapped out the entire surface Brillouin zone along the nearest neighbor and next nearest neighbor azimuths, <011> and <121>, respectively. Our experimental results are in excellent agreement with density functional perturbation theory calculations, which provide a detailed description of the dispersion curves. The combination of experimental measurements with theoretical calculations allows us to determine the interfacial Si-Si force constants, including coupling between the molecular adlayer and the substrate, displacement fields, and mode polarizations. Helium atom scattering complemented with DFPT calculations allow us to quantify these effects. Additionally, isotopic effects were probed by mapping the dispersion curves for the perdeutero-methylated silicon surface. Our results will be discussed with respect to hydrogen-terminated Si(111).