C-60 cluster films have been prepared by thermal evaporation in nitrogen or argon atmosphere. Surface morphologies and optical properties of C-60 cluster films were studied with scanning electron microscope, ultraviolet-visible spectroscopy and ellipsometry. The average diameter of the surface particles of C-60 cluster films increases with pressure. The UV/VIS absorption spectrum of C-60 films grown in N-2 or Ar atmosphere are significantly different from that of C-60 films grown in vacuum. The three feature peaks of C-60 films have obvious red shift. The value of red shift of three feature peaks is 6.0, 19.0 and 20.5 nin for C-60 films deposited in an Ar pressure of 16 kPa, and 8.0, 28.0 and 28.5 run for C-60 films deposited in an N-2 pressure of 16 kPa. The value of red shift increases with increasing wavelength. The refractive index n varies from 1.49 to 1.42 for C-60 films deposited in Ar atmosphere and from 1.46 to 1.07 for C60 films deposited in N-2 atmosphere with gas pressure varying from 4 to 16 kPa. The bandgap of C-60 films deposited in Ar and N-2 atmosphere is 2.24 and 2.09 eV, respectively. They are larger than that of C-60 films (2.02 eV) deposited in vacuum. These results indicate that the optical properties of C-60 cluster films are related to the nature of gas and pressure during deposition. The effects of gas and pressure on surface morphology and optical properties have been studied. (c) 2005 Published by Elsevier B.V.