Research

Our research interests lie in exploring the local electronic, magnetic, and mechanical properties of atomic and molecular structures at surfaces. We are interested in studying how local interactions between atomic-scale structures affect their microscopic behavior, and how quantum mechanical effects might influence nanodevice behavior in very small structures. Our main experimental tool is scanning tunneling microscopy (STM), which we use in combination with other experimental tools to both fabricate atomic-scale structures and probe them spectroscopically.

Carbon Nanostructures

New classes of carbon nanostructures such as monolayer graphene, graphene nanoribbons, fullerenes, and nanotubes are extremely flexible and hold great promise for new generations of nanodevices. We are currently using scanned probe techniques to explore and modify the properties of these materials at the atomic scale, as well as investigate their device potential. Read more...

Molecular Machines

Though historically difficult to control at a truly molecular level, NEMS (nano-electro-mechanical systems) have exciting potential to advance technological applications. With STM, we explore the physics of new bottom-up fabricated molecular structures whose electro-mechanical state can be remotely switched with light. Our goal is to assemble these structures into functional molecular machines. Read more...
The mechanical oscillatory response of surface-adsorbed molecules are also within the scope of this project. The vibrational properties of molecules are typically probed via infrared and Raman spectroscopies. In our lab we have been developing new techniques, referred to as IRSTM, that combine infrared spectroscopy (IR) and STM. Read more about our advances in this direction...

Spin-Polarized Nanostructures

When magnetic structures are shrunk down to single-atom or single-molecule sizes, quantum spin effects dominate their behavior. Interest in this area derives from its great promise for revolutionary applications in spintronics and quantum information. Our group is using scanned probe techniques to explore individual magnetic atoms, spin clusters, and magnetic molecules.

Nanophotovoltaics

Current state-of-the-art solar cells require carefully processed semiconducting interfaces that extend over macroscopic distances (i.e., extended p-n junctions). An alternative method for creating solar cells, however, is to engineer nanoscale elements that can be combined to create microscopic p-n junctions. These can then be combined in large quantities to create composite photovoltaics with spatially distributed p-n interfaces. A benefit of this approach is that such nano-photovoltaic building blocks can be mass-produced cheaply and so this technique is potentially more scalable than current state-of-the-art semiconductor photovoltaics. The downside is that nano-photovoltaics currently have very low efficiencies. Our group is currently exploring the microscopic physics of nano photovoltaic interfaces, with the goal of understanding and optimizing the processes that allow us to convert sunlight into usable electrical energy in molecular-scale structures.