SURFACE MORPHOLOGY OF THE FILMS OF THE C60/C70 FULLERENE MIXTURE. IDENTIFICATION OF C60 AND C70 IN THE C60/C70 FILMS USING ABSORPTION SPECTRA

Films of the C60/C70 mixture are deposited onto various substrates in a vacuum of 6.5 mPa using the thermal sublimation method. The surface morphology of 195-nm C60/C70 films is studied. It is found that polycrystalline and quasi-amorphous C60/C70 films are formed on silica and copper substrates, respectively. The nature of the C60 and C70 absorption bands has been discussed in detail by analyzing the literature and our data. The absorption spectra of the C60 and C70 films and the C60/C70 mixture films are described as the sum of Gaussian functions. The absorption bands of C60 (at 2.474, 3.440, and 3.640 eV) and C70 (at 2.594, 2.804, 3.018, and 3.252 eV) can be used to identify those substances in fullerene mixtures. C60 is found to be the dominant component in the C60/C70 films.