Analytical microscopy uses various high-resolution techniques to obtain information about materials on the atomic scale. It is one of the most powerful tools available for understanding a material's basic structure, chemistry, and morphology. We use two complementary types of analytical microscopy — electron microscopy and scanning probe microscopy — together with a variety of state-of-the-art imaging and analytical tools to capture data about photovoltaic (PV) materials and devices.
Electron microscopy generates images caused by electron beams rather than light. Scanning electron microscopy deals with bulk samples, while transmission electron microscopy probes the properties of thin foils. These two techniques are particularly well suited for investigating the crystallinity of materials, structural defects, chemical composition, surface topography, and the electrical and optical properties on the nano or sub-nano scale.
Proximal probe techniques measure the force between a material and a probe tip placed extremely close to the material surface. We primarily use atomic force microscopy and scanning tunneling microscopy to measure force created by applying a voltage bias, with the former at atmospheric pressure and the latter in a vacuum. They are particularly valuable for mapping topography and electronic properties of material surfaces at resolution up to atomic scale.
We also use a dual-beam focused ion-beam work station to prepare samples for electron microscopy. We use electron probe microanalysis for compositional analysis. We also design and build custom instrumentation, and develop unique analytical microscopy techniques for studying materials and devices.