Morphology and characteristics of C-60 thin films grown in argon atmosphere by thermal evaporation

The surface morphology, structure, and optical absorption characteristics o f C-60 thin films grown in argon atmosphere by thermal evaporation have bee n studied. X-ray diffraction studies reveal a mixture phase of face-centere d-cubic and hexagonal-close-packed phases fur this film. Infrared analyses show no evidence of chemical change. The observations of atomic force micro scopy of C-60 thin films grown in argon atmosphere found that surface parti cles are larger and sharper than that grown in vacuum, thus C-60 thin films grown in argon atmosphere may be advantageous to using C-60 for electron f ield emission. Ultraviolet-visible optical absorption spectrum of this film in the range of wavelength from 200 to 600 nm is very different than that of the film obtained under vacuum conditions. The position and intensity of absorption peaks are obviously changed compared to vacuum C-60 thin film. The band gap energy of this film also changes from 2.02 to 2.24, eV compare d to the film prepared under vacuum. (C) 2001 American Vacuum Society.