Abstract
Off-axis electron holography in the transmission electron microscope is a powerful interferometric technique that enables electrostatic and magnetic fields to be imaged and quantified with spatial resolution often approaching the nanometer scale. Here, we demonstrate the capabilities of the technique for phase quantification at the nanoscale by briefly reviewing some of our recent studies of nanostructured materials. Examples that are described include determination of the electrostatic potential profiles associated with doped Si- and GaAs-based semiconductor devices, measurement of hole accumulation in Ge quantum dots, mapping of polarization fields in III-nitride heterostructures, and observation of the remanent states and reversal mechanisms of lithographically patterned magnetic nanorings. Some issues associated with sample preparation for doped semiconductor heterostructures are also briefly discussed.
Original language | English (US) |
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Pages (from-to) | 375-382 |
Number of pages | 8 |
Journal | Ultramicroscopy |
Volume | 110 |
Issue number | 5 |
DOIs | |
State | Published - Apr 2010 |
Funding
We are grateful to Dr. P.L. Fejes (Freescale Semiconductor), Dr. S.R. Johnson and Prof. Y.-H. Zhang (ASU), A. Mouti and Prof. N. Grandjean (EPFL, Lausanne, Switzerland) and J. Leach and Prof. H. Morkoc (Virginia Commonwealth University) for providing samples and for ongoing collaborations. We also acknowledge use of facilities in the John M. Cowley Center for High Resolution Electron Microscopy and the Center for Solid State Electronics Research at Arizona State University. Financial support for this work came primarily from DOE Grant DE-FG02-04ER46168 , with additional support for the nitride studies coming from Contract FA8650-08-C-1395 from Wright Patterson Air Force Base (Monitor: C. Bozada) . Finally, we express our appreciation to Hannes Lichte for his encouragement, support and valuable advice over many years.
Keywords
- Magnetization reversal
- Off-axis electron holography
- Polarization fields
- Semiconductor devices
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Instrumentation