The adsorption of C60 and C84 on the Si(100)2×1 surface is investigated by using the scanning tunneling microscope (STM) and the scanning tunneling spectroscope (STS). Both of the molecules occupy the trough surrounded by four neighboring dimers. The results show that both C60 and C84 form strong bonds with the Si substrate. Multiple-layer adsorption of C60 and C84 results in formation of ordered crystalline islands with the fcc(111) configuration. The internal structures have also been observed for the C60 and C84 molecules of the first layer adsorbed on the Si(100) surface. In the case of the C84 molecules, those of the ordered multiple-layer surface also show similar internal structures. We take these STM images as evidence that the rotation of the individual fullerenes is suppressed significantly on the Si surface. Comparing with the theoretical results, these STM images are attributed to the reflection of the partial charge density of the states of the molecule near the Fermi level. The electronic structures characterized by STS are in good agreement with the recent theoretical calculation and show significant charge transfer from the Si substrate to the adsorbates.
ASJC Scopus subject areas
- Condensed Matter Physics