Research Description

I am interested in surface physics at the nanometer-scale in condensed systems. In practical terms, can I build an electronic device out of a single molecule? Insight into critical technological problems, such as molecular-scale electronics, molecular light-emitting diodes, and light harvesting systems, relies on understanding fundamental physical processes at the nanometer scale. When a single molecule is placed between two electrodes, what is its electrical conductivity? How does light modify the molecule's electrical properties?

My focus is to understand the electronic and the optoelectronic characteristics of individual molecules and functional nanometer-scale assemblies. The experimental approach is to combine the molecular-scale resolution of scanning probe techniques, such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM), with optical spectroscopy.

We use self-assembled monolayers (SAMs) as a matrix platform in which other molecules can be tethered. SAMs have the advantage that they can be easily prepared under bench-top conditions and their molecular components can be readily imaged by STM. Our recent work has concentrated on developing methods for natural patterning of SAMs on the nanometer scale, including surface-structure directed chemistry. We have a strong collaboration with Ron Halterman's synthetic organic group in chemistry to make the unique molecules used for our work. We have also developed flat gold nanoparticles (FGNPs) as plasmonic substrates for our STM studies. In addition to STM, my group also has developed capability in single nanoparticle spectroscopy for molecular plasmonics and in grazing angle-infrared spectroscopy for SAM characterization. Our group is also interested in developing novel scanning probe techniques.