Self-assembled monolayers (SAMs) of alkanethiols on Au(111) have been of great interest for decades. The formation of thiol-based SAMs on Au(111) has been of particular interest due to their ease of formation and tunability. The advent of the scanning tunneling microscope (STM) has allowed scientists to further their understanding of the mechanisms by which SAMs form. While much research has been done on SAMs and how they form, there is still much to be discovered. In this thesis, the diffusion of three different SAM coated Au(111) samples were studied via STM. The first project focuses on a two-dimensional gas phase of the molecules which prevented immobilization of the gold surface. The factors potentially affecting the rate of decay of the various samples are also discussed. The second project discusses preliminary results into how STM scanning current affects octanethiol monolayers. Generally, a higher tunneling current results in more molecular motion on the surface.

Self-assembled monolayers have shown a lot of promise for use in technological applications including microelectronics and photovoltaics. Especially structures that contain molecules with light-accepting (e.g. porphyrins) or electron transfer (e.g. fullerenes) properties are of great use. The goal of the studies discussed in this dissertation is to use nickel porphyrins and C60 fullerenes to build supramolecular assemblies on a Au(111) substrate and study the resulting structures using scanning tunneling microscopy (STM) and spectroscopy (STS). In order to achieve our goal we first need to understand the basic structure of the gold reconstructed surface and of C60 single and double layers on gold. Both of those structures have been studied in detail during the last 25 years and our results as shown in Chapter 3 correspond well with literature studies.

Nanostructures refer to materials that have relevant dimensions on the nanometer length scales and reside in the mesoscopic regime between isolated atoms and molecules in bulk matter. These materials have unique physical properties that are distinctly different from bulk materials. Self-Assembled Nanostructures provides systematic coverage of basic nanomaterials science including materials assembly and synthesis, characterization, and application. Suitable for both beginners and experts, it balances the chemistry aspects of nanomaterials with physical principles. It also highlights nanomaterial-based architectures including assembled or self-assembled systems. Filled with in-depth discussion of important applications of nano-architectures as well as potential applications ranging from physical to chemical and biological systems, Self-Assembled Nanostructures is the essential reference or text for scientists involved with nanostructures.