Electron-stimulated reaction of C60 with a model etching gas, SF6

High-resolution electron energy loss spectroscopy has been used to characterize changes induced in C-60 films due to electron-stimulated reaction with SF6, a standard etching gas. A monolayer of SF6 was adsorbed at low temperature on 4 monolayer thick C-60 films grown on Au(110). The C-60 vibrational modes and SF 6 vibrations observed were essentially unshifted from the pristine solid state and gas phase values, respectively, indicating a van der Waals-type interaction between SF6 and C-60. These surfaces were subsequently irradiated with electrons of energy between 15 and 230 eV, stimulating a reaction between C-60 and the adsorbed SF6. At low electron beam energy and electron dose (E = 15 eV, 1.5 X 10(-3) C cm(-2)), the electron- stimulated reaction of SF6 with C-60 induces some disorder within the films, and subtle changes are observed in the vibrational spectra. At higher beam energy and electron dose (E = 230 eV, 4.7 X 10(-3) C cm(-2)), significant changes occur in the films as demonstrated by the appearance of strong disorder. The resulting material appears to have a graphite-like local structure. Several new vibrations are observed and may be due to the formation of graphitic sheets. (C) 1998 American Institute of Physics. [S0021-8979(98)02320-2]