Tunneling spectroscopy of fullerene/Ge multilayer systems

We report on an IETS (inelastic electron tunneling spectroscopy) technique which has successfully resolved 20 of the 46 C-60 intramolecular vibrationa l modes and similar to 50 of the 122 modes of C-70. By layering thin, therm ally evaporated films of germanium and fullerene molecules, composite multi layer tunnel barriers are formed which appear to produce enhanced IET resul ts. IETS is in general not selection-rule restricted and has the potential to present all non-degenerate vibrational modes. (C) 1999 Elsevier Science B.V. All rights reserved.