BRILLOUIN-SCATTERING OF CLUSTER-ASSEMBLED CARBON-FILMS

The low frequency vibrational spectrum of cluster beam deposited carbo n films was studied by Brillouin light scattering. In thin films the v alues of both bulk modulus and shear modulus has been estimated from t he shifts of surface phonon peaks. The values found indicate a mainly sp(2) coordinated random network with low density. In thick films a bu lk longitudinal phonon peak was detected in a spectral range compatibl e with the value of the index of refraction and of the elastic constan ts of thin films. High surface roughness, combined with a rather stron g bulk central peak, prevented the observation of surface phonon featu res. (C) 1998 Elsevier Science Ltd. All rights reserved.