Scanning Tunneling Microscopy of C60 and C70 on Ordered Au(111) and Au(110):Molecular Structure and Electron Transmission

摘要

Scanning tunneling microscopy (STM) images are reported for C60 and C70 layers onordered Au(lll) and (110) surfaces in air and in aqueous 0. 1 M HC104. Hexagonal close-packed layers were obtained for both C60 and C70 on Au(lll); however, the latter feature distortions consistent with the presence of groups of standing-up and lying down C70 orientations. While the fullerene layers are less ordered on Au(110), the molecules are more rigidly held and can yield STM images with resolved intramolecular carbon rings. The likely modes of tipsurface electron tunneling via the adsorbed fullerenes, involving superexchange coupling, are discussed briefly in the light of the observed STM imaging properties.