Large area self-ordered parallel C60 molecular nanowire arrays on Si(110) surfaces

Abstract

We report that the large-scale self-organization of well-ordered parallel C60 molecular nanowire arrays with tunable structures on Si(110) surfaces can be achieved through a site-selective anchoring method. Our scanning tunneling microscopy investigations show that the preferential trapping of C60 molecules atop Si pentagons on upper terraces of the C60-induced Si(110) reconstructed surface leads to the formation of long-range ordered C60 molecular nanowires with a C60 triplet as a repeat unit along each Si upper terrace (i.e., a Si nanowire). Scanning tunneling spectroscopy measurements show a large energy gap of ∼3.0 eV between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the C60 molecules within a C60 triplet, indicating a relatively weak C60–Si(110) interaction that is the main driving force for the site-selective anchoring atop Si pentagons via the geometric matching. The formation of ordered parallel C60-tetramer nanowire arrays upon further C60 adsorption confirms this self-ordering mechanism. Such mesoscopically ordered hybrid C60/Si nanojunction arrays with the unmodified C60 on periodic Si nanowires were not yet observed before. The ability to grow the large-area parallel fullerene nanowire arrays with tunable structures on Si(110) represents an important step toward the engineering of advanced Si-based molecular nanoelectronics and quantum computation.