Functionalization of scanning tunneling microscope probes with buckminsterfullerenes

Abstract

This dissertation analyzes the feasibility and advantages of molecular functionalization of scanning tunneling microscope (STM) probes with buckminsterfullerenes. The C$\sb{60}$ molecules are adsorbed onto the tunneling region of a STM tip by rastering the tip in a thin film of C$\sb{60}$ 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.