Skip to content Skip to main navigation Report an accessibility issue



Microscopy techniques used by the group include in-house STM and AFM, as well as SEM, STEM, and HRTEM which are available at the Center for Nanophase Materials Science (CNMS) located at ORNL.

Scanning Tunneling Microscopy (STM)

A Scanning Tunneling Microscope (STM) operating in air and at room temperature has been designed and constructed. Plans are underway to construct a low-temperature STM which operates in ultra-high-vacuum. Calibration and exploratory measurements have been performed using graphite single crystals. These studies have produced high quality images in atomic resolution: The first STM experiments used freshly cleaved graphite crystals and those coated with several different liquid crystal films.

Shown above is an STM picture of a film of 6CB liquid crystals (4-n-hexyl-4′-cyano-biphenyl) on a graphite single crystal. Early results are extremely encouraging. This device is intended to act as another complementary instrument to the surface studies effort. The group also makes use of its commercially available NanoScope III SPM By Digital Instruments, Inc.

Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM), High Resolution Transmission Electron Microscopy (HRTEM)

The group currently has access to a Hitachi S4700 SEM and HD2000 STEM, which are located at the CNMS at ORNL. These instruments are essential to the synthesis and catalysis work done in the group. Both, the SEM and the STEM have the capability of performing Energy Dispersive X-ray Spectroscopy (EDXS). Elemental mapping and line scans are also possible using the STEM. We are currently obtaining access to use the HRTEM so we can perform nanodiffraction measurements of our synthesized nanoparticles.