An STM study of C\(_{60}\) molecule on Au(111): close-packed single layer and magic number clusters

Xie, Yangchun (2014). An STM study of C\(_{60}\) molecule on Au(111): close-packed single layer and magic number clusters. University of Birmingham. Ph.D.

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Abstract

This thesis includes the results of the investigation of the C\(_{60}\) layer on Au(111), and the self-assembled C\(_{60}\)/Au complex supported on Au(111) by Scanning Tunnelling Microscopy.

The characteristics of the close packed C\(_{60}\) layer on metallic surfaces indicate a complex bonding geometry of the molecules with the surfaces, where the mechanisms behind various observations remain to be uncovered. The interfacial interaction of the C\(_{60}\) layer on the Au(111) substrate under ultra high vacuum conditions is investigated. The symmetry and lattice mismatch of the C\(_{60}\) layer and the Au crystalline substrate leads to the formation of three phases of the molecular layer, with brightness contrast among the C\(_{60}\) molecules. The epitaxial configuration of the molecules on the substrate is analyzed from a geometric point of view. And the interfacial diffusion and nucleation of Au atoms deposited on the C\(_{60}\) layer covered Au(111) sample, reveals the bonding difference between the dim and the normal (also named bright) C\(_{60}\) molecules. We also propose that the C\(_{60}\) layer can be used as a mask to guide the structures of Au islands nucleated at the interface between the C\(_{60}\) overlayer and the metallic substrate.

Self-assembly of molecules on well-defined surfaces is a promising route to producing functional structures with nanoscale dimensions. Taking advantage of this approach, we obtained C\(_{60}\)/Au clusters with specific size, shape, and organization of nanostructures, based on both the van der Waals interaction between C\(_{60}\) molecules and the interaction between the molecule and the Au atoms through charge transfer. The structural models for the C\(_{60}\)/Au clusters observed are presented, based on knowledge about the C\(_{60}\) molecules on the Au(111) surface. The Au(111) substrate with the 22×√3 reconstruction acts as a template to regulate the growth of the cluster, and plays a vital role in the size distribution and in the thermal stability of the clusters.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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