Events

Department of Physics Seminar Series: Sergei Rouvimov
Monday, February 5, 2018 - 3:15pm

SB1 107, 1025 SW Mill Street
Free and open to the public
Light refreshments will be served

 

Dr. Sergei Rouvimov
Department of Electrical Engineering
University of Notre Dame
"Transmission Electron Microscopy of Nanostructures"

 

Transmission Electron Microscopy (TEM) is a key metrology for characterization of atomic structure and composition of wide variety of nano-structures including MBE grown semiconductor structures (e.g. GaN/AlGaN QWs, InAs/ GaAs QDs, and 2D materials), chemically synthesized metal and perovskite nano-particles, SHS synthesized nano-materials, and many others.

Recent developments in TEM have enabled characterization of the structure and composition of nano-materials at the atomic level to establish the relationships between their structure and physical properties.  Modern electron microscopes allow observation of individual atoms and can detect a compositional variation in crystals within an atomic column. TEM and STEM imaging at the atomic level, in combination with electron diffraction and composition analysis at atomic and nanometer levels, is available in majority of modern electron microscopes. This provides researchers with unique and powerful “tool-kit” to solve complicated materials problems in a fast and efficient manner.

For cross-sectional TEM of hetero-structures, the Focus Ion Beam (FIB) became a routine technique.  However, FIB preparation can be a challenging task in case of radiation sensitive materials (such as graphite, CaF2, etc.). To assure a good quality of TEM sample, thin foils prepared by FIB need to be further cleaned (e.g. by low energy plasma) in order to remove the surface damage and contamination. The artifact-free TEM samples are necessary for reliable information on atomic structure and composition. In addition, atomic modelling, HRTEM image processing, and image simulation by commercial software packages are often necessary to support the TEM analysis, especially in case of novel nano-materials. 

Because modern electron microscopes are often fully computer controlled, their operation has become easy for young researchers like graduate students who can get an access to expensive and sophisticated scientific equipment after appropriate training. Therefore, education in the area of electron microscopy materials sciences is an important mission of many electron microscopy centers.

 

The Department of Physics

www.pdx.edu/physics | physics@pdx.edu | 503-725-3812
For more information about our upcoming seminars please see our seminars and events webpage
To be added to our mailing list for seminars and events please send us a request by email.