Photo-assisted structural transition and oxygen diffusion in solid C60 films

Using Raman scattering we have observed a phototransformation of C60 films on Si(100) from a face-centered-cubic (fcc) phase to a second solid phase leaving the C60 molecules intact. Furthermore, photoassisted oxygen diffusion into the deep bulk is detected using alpha resonance scattering. The Raman spectrum for oxygen-doped C60 is found to be similar to the result for oxygen-free fcc C60, and oxygen is found to harden the film against phototransformation.