Our goal is to develop low-energy transmission electron diffraction, imaging, and spectroscopy in the scanning electron microscope (SEM), for determining microscopic structure, defect types, and interface character in structural materials; ultrathin films; nanoparticles; and potentially, biological material systems. Successful adaptation of transmission electron microscopy (TEM) concepts to the SEM can lead to numerous potential impact areas in the characterization of materials, including significantly increased quantitative analytical capabilities in the SEM, improved crystallographic analysis associated with defect and texture characterization from thin samples, and broader possibilities for quantitative in situ/in operando studies in the electron microscope. These impacts arise due to physical phenomena specific to the SEM: compared to conventional TEM methods, lower SEM beam energies lead to increased electron scattering cross sections (resulting in increased contrast from very small volumes of material), and reduced beam-induced knock-on damage (resulting in prolonged imaging times and fewer artifacts). Research includes developing and demonstrating diffraction, imaging, and spectroscopy methods on difficult-to-characterize material systems; modeling electron scattering as well as damage formation in such materials; and integrating multiple characterization methods to enable simultaneous capture of different signals. Our laboratory has three scanning electron microscopes (one being variable-pressure, one being environmental) with automated electron backscatter diffraction systems, multiple SEM-based transmission electron detectors, two 200 kV transmission electron microscopes, a dual-beam focused ion beam system, and specimen preparation facilities.

 

key words

EBSD; Electron backscatter diffraction; Electron microscopy; Material characterization; Nanotechnology; Nanoparticles; SEM; STEM-in-SEM; TEM-in-SEM; TKD; Transmission EBSD; Transmission Kikuchi diffraction; Transmission scanning electron microscopy; TSEM;

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral applicants