RICE UNIVERSITY Functionalization of Scanning Tunneling Microscope Probes with Buckminsterfullerenes

This dissertation analyzes the feasibility and advantages of molecular functionalization of scanning tunneling microscope (STM) probes with buckminsterfullerenes. The C60 molecules are adsorbed onto the tunneling region of a STM tip by rastering the tip in a thin lm of C60 vacuum deposited on graphite. The individual tip-adsorbed molecules are subsequently imaged in situ by scanning the fullerene-adsorbed tip over a defect covered graphite surface. These nanometer-size defects serve as a surface tip array which images the molecules adsorbed to the tip when the surface is scanned. It is then demonstrated that the fullerene-adsorbed STM tips can be used to observe electron scattering from point defects and steps on graphite. This cannot be observed using bare metal tips. Molecular functionalization adds a new dimension to scanning tunneling microscopy by allowing greater control of the electronic interactions between the tip and sample.