Self-assembly of C[formula omitted] layers at Tl/NiSi[formula omitted] atomic sandwich on Si(111)

Abstract

Self-assembled growth of C60 monomolecular layers at the atomic sandwich consisting of Tl-covered single-layer NiSi2 on Si(111) has been studied as a function of the density of the Tl atomic layer. It has been found that C60 fullerenes form hexagonal close-packed arrays. Within a C60 layer, fullerenes can form together with Tl atoms three distinct configurations which are reflected by difference of the C60 brightness, labelled as dim, normal and bright, in the scanning tunneling microscopy images. It has been elucidated that the bright fullerenes reside atop a completed Tl monolayer, in the case of the normal fullerenes one Tl atom directly beneath the given fullerene is missing, and under the dim fullerenes no Tl atoms are left. Using Tl deposition, it is possible to change the relative fractions of the dim, normal and bright fullerenes, in particular to fabricate the homogeneous C60 layers consisting exclusively of the fullerenes of a single type, normal or bright, depending on the desire.