Study of Microstructure and Interfacial Interaction in Al–C60 Co-Evaporated Films

Abstract

Al–C60 thin films were prepared in vacuum by the co‐evaporation method. The structural and physical properties of the films have been studied with transmission electron microscopy and Raman scattering spectra. The growth of C60 crystallites is significantly limited by co‐deposition of aluminum. Raman spectra showed in these films that the Ag(2) pentagon‐pinch mode of C60 splits into two peaks, corresponding to the pristine and softened Ag(2) modes, respectively. The shifts of the softened Ag(2) mode are about 6 to 9 cm—1, and depend weakly on the microstructures of the films. In addition, there is a substantial variation of the ratio between the intensity of the softened and unsoftened Ag(2) mode. The experimental results could be understood based on the model of Al–C60 interfacial interaction.

Evidence for metal-C60 interface interaction from Raman spectroscopy

“…It is also possible that in the latter regions negative charge transfer also occurs, but is counterbalanced by the oxidation-induced positive charge. A g (2) mode splitting due to charge transfer has also been reported in co-evaporated Al-C 60 films, 8 suggesting charge-transfer regions insulated from the rest of fullerite matrix.…”

“…Q a , w a , data for additional features. in Al-C 60 co-evaporated films, 8 and also in Al-C 60 multilayers. 24 In our Cu-C 60 samples, H g 8 increases whereas H g 7 remains weak and broadens (Fig.…”

“…TEM and Raman spectroscopic data on Al-C 60 co-evaporated films have also been reported. 8 Raman spectroscopy is a powerful tool for studying the vibrational properties of solids, as affected by electrical charge and disorder of various types. This work was aimed at investigating the M-C 60 interface interaction in Cu-C 60 nanosystems via the induced alteration of intramolecular vibrational modes of the C 60 matrix, as revealed by Raman spectroscopy.…”

Formation Process of AlN Through Precursors and Its Application to Joining AlN Ceramics

“…Among these, endohedral, Al‐coated, Al‐intercalated, and AlN fullerenes are inconsistent with the results, as explained by the following analysis: The endohedral fullerenes should cause hyperfine interactions with the central nitrogen atom ( I = 1) and aluminum ( I = 5/2), in the ESR measurements, but their ESR signals were not detected in the AlN precursor. In the cases of Al‐coated and Al‐intercalated fullerenes, their crystalline structures were reported to be fcc, which is different from that of the AlN precursor. AlN fullerenes are not observed experimentally, but their geometrical structures and electronic properties have been investigated theoretically .…”

Mechanical and optical characteristics of Al-doped C60 films

“…To investigate the feasibility of C 60 layers, it is inevitable to obtain stronger and more stable C 60 films, keeping the original characteristics of C 60 films. It has been reported that the metal-C 60 interaction is stronger than the C 60 -C 60 van der Waals interaction [9][10][11]. Therefore, metal doping in C 60 films may produce much harder and chemically stable materials.…”