Photoluminescence Spectra of C60 Thin Films Deposited on Different Substrates

We report on photoluminescence (PL) spectra from 10 to 300 K of C-60 thin films deposited on Si, GaSe, GaAs and Au substrates. X-ray diffraction patterns evidence a polycrystalline structure of the films. The effect of the different substrates on the C-60 PL spectra and the influence of the deposition parameters, such as the deposition rate and substrate temperature on the luminescence efficiency of the C-60 films are investigated. PL bands of the films deposited at low temperatures and high deposition rates are wider and less resolved because of the increased structural disorder of the films. The main feature of the PL spectra of the C-60 films is the zero-phonon exciton line together with its phonon replicas