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Materials Science at Oregon State University

Tools for in-situ and operando microscopy—how to bring your bench top experiment inside the microscope

Date: Thursday, Apr 19th
Presenter: Dr. Khim Karki, Hummingbird Scientific


I will present an overview of sample holders that broaden the stimuli “knobs”—environment, temperature, electric field, etc.—that can be used to observe, with high-spatial resolution, a specimen or device in an electron or x-ray microscope under realistic operating conditions. For example, with a standard transmission electron microscopy (TEM) sample holder specimens are observed at low pressures (~ 10^-7 mbar) that are incompatible with liquid or gas environments. Now, however, with micro-sized liquid cells we can observe samples submerged on a thin liquid layer routinely in a TEM. I will discuss several examples of this approach where different sample holders have been used to study crystal growth, self-assembly of particles in liquids, oxidation and reduction reactions in gas environments, 2D-based MEMS devices, and the charging of a battery’s primary particles.

Dr. Khim Karki is an Application Scientist at Hummingbird Scientific in Lacey, WA. Prior to joining Hummingbird, Dr. Karki was a Postdoctoral Research Associate at Brookhaven National Laboratory, Upton, NY. Dr. Karki received his PhD from University of Maryland in 2013.

Dr. Karki’s research interests include materials for energy applications and development of in-situ TEM tools and techniques for materials research. Dr. Karki can be reached at khim_karki@hummingbirdscientific.com or (360) 252-2737 ext 129