CHE 598 seminar by Dr. Daniel Perea
About the event
“Enabling New Science with Atom Probe Tomography via Environmentally Protected Specimen Handling” presented by: Dr. Daniel Perea
BIOGRAPHY:
Dr. Perea is a senior staff scientist at the Environmental Molecular Sciences Laboratory at the Pacific Northwest National
Laboratory. He received his Ph.D. in Materials Science & Engineering from Northwestern University in 2009, where he established
the application of APT to directly map dopant impurity incorporation in low-dimensional semiconductor nanostructures. His current
interests at PNNL include developing unique cryogenic-based and environmentally protected techniques and protocols to pioneer
the use of APT to probe the composition and structure of environmentally sensitive materials related to energy and the
environment.
ABSTRACT:
The liquid/solid and gas/solid interface represents a rich scientific and technological frontier for discovery and innovation in many
areas of science. However, the direct nano- to atomic-scale characterization of these interfaces is technically challenging within
broad range of analytical tools that require high to ultrahigh vacuum conditions. This challenge has been largely addressed within
the electron microscopy community through the development of unique specimen holders and differentially-pumped vacuum
systems that allow researchers to probe, in situ, liquid/solid and gas/solid interfaces using electron probes. However, the direct
application of APT to liquid/solid and gas/solid interfaces is not possible and requires the development of unique specimen
preparation and handling of cryogenically-frozen specimens and/or work with specimens under environmentally-protected
conditions enabling controlled gas exposures. At PNNL, we have developed a unique suite of hardware and experimental
protocols for the preparation, handling, and analysis of environmentally-sensitive materials centered around a unique
environmental transfer hub, in situ environmental chemical reactor, specimen suitcase device, and modified cryo FIB/SEM
capabilities. The ability to prepare, manipulate, and transfer specimens under either cryogenic or vacuum conditions thus provides
a means to uniquely apply APT analysis to a wide variety of material systems that would not be possible otherwise. Here I will
describe some new science areas relevant to structural biology and catalysis that can be explored with APT analysis applied to
temperature sensitive material systems requiring cryo specimen preparation and transfer, as well as air sensitive material systems
requiring vacuum or inert vacuum transfer following controlled gas exposures.