CHEMISORPTION EFFECTS ON THE DYNAMICS OF GE CLUSTERS AND ULTRATHIN FILMS

Interference-enhanced, in situ Raman scattering has been used to study clusters and ultrathin films of Ge sputter-deposited on C films in ultrahigh vacuum. Measurements of the two polarization components of the Raman scattering are found to yield amorphous-like spectra that are modified by dangling bonds. Large concentrations of dangling bonds at cluster surfaces result in a reduction of the high-frequency optic phonon peak due to changes in the local dynamics. Chemisorption of H and O on these clusters and ultrathin films saturates these dangling bonds, removing the large size-dependent shift and reducing the relative intensity of low-frequency scattering. These effects are attributed to the rehybridization of the orbitals of back-bonded Ge cluster atoms.