Film growth and surface reactions ofC60onSi(100)H(2×1)

Abstract

High-resolution electron-energy-loss spectroscopy (HREELS) has been used to characterize ${\mathrm{C}}_{60}$ films up to 4 monolayers thick grown at room temperature on hydrogen-terminated Si(100). Our results show that compared with ${\mathrm{C}}_{60}$ films on clean Si(100) surfaces a considerably higher degree of order in the as-deposited films is achieved. At low coverages the observed ${\mathrm{C}}_{60}$ vibrational modes and the Si-H vibrations of the substrate are essentially unshifted, indicating a van der Waals–type interaction between ${\mathrm{C}}_{60}$ and $\mathrm{Si}\mathrm{}\left(100\right)\mathrm{}\mathrm{H}(2\mathrm{}\times 1)$. After annealing at 450 K the film order is substantially increased. Annealing at 600 K results in desorption of the ${\mathrm{C}}_{60}$ multilayers and a hydrogen-transfer reaction from the surface to the adsorbed monolayer molecules. When annealing the sample at 800 K, the remaining surface terminating hydrogen desorbs and evidence for a change in the ${\mathrm{C}}_{60}$ bonding configuration is found. Finally, flashing the sample at 1300 K leads to the formation of silicon carbide.