Materials Applications of Aberration-Corrected STEM

Book · Tue Jan 01 04:00:00 EST 2008

OSTI ID:1021943

Pennycook, Stephen J ^[1]; Chisholm, Matthew F ^[1]; Lupini, Andrew R ^[1]; Varela del Arco, Maria ^[1]; van Benthem, Klaus ^[1]; Borisevich, Albina Y ^[1]; Oxley, Mark P ^[1]; Luo, Weidong ^[1]; Pantelides, Sokrates T. ^[2]

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1. ORNL
2. Vanderbilt University

The VG Microscopes 100 kV and 300 kV scanning transmission electron microscopes at Oak Ridge National Laboratory were equipped with Nion aberration correctors several years ago. This chapter reviews our experience with these correctors, specifically, the reduction in probe size by more than a factor of two and the associated benefits for materials research, which extend far beyond improved resolution. A smaller, brighter probe brings enhanced image contrast and signal to noise ratio, making it possible to image light atom columns in materials such as oxide perovskites. It vastly increases the sensitivity to single atoms, both for imaging and electron energy loss spectroscopy. In addition, aberration correction greatly improves the collection efficiency for bright field phase contrast imaging, allowing simultaneous, aberration-corrected, Zcontrast and phase contrast imaging. Finally, the larger probe-forming aperture gives a reduced depth of field, giving a depth resolution less than the thickness of a typical specimen. It becomes possible to focus directly on features at different depths in the specimen, and three-dimensional information can be extracted with single atom sensitivity. In conjunction with density functional and elasticity theory, these advances provide a new level of insight into the atomistic origins of materials properties. Several examples are discussed that illustrate the potential for applications including the detection of orbital occupation stripes and interface stacking in complex oxides, the mechanism for improved critical currents in Ca-doped grain boundaries in high-Tc superconductors, the segregation of rare earth dopants in Si3N4 grain boundaries, the quantitative analysis of strain-induced growth phenomena in semiconductor quantum wells, the determination of the three-dimensional distribution of stray Hf atoms in a high dielectric constant device structure, and the origin of the remarkable catalytic activity of Au nanoparticles

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1021943
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
APERTURES
ATOMS
CORRECTIONS
CRITICAL CURRENT
DENSITY FUNCTIONAL METHOD
DEPTH
EFFICIENCY
ELASTICITY
ELECTRON MICROSCOPES
ELECTRONS
ENERGY-LOSS SPECTROSCOPY
GRAIN BOUNDARIES
GROWTH
HIGH-TC SUPERCONDUCTORS
HYPERFINE STRUCTURE
IMAGES
INTERFACES
LEVELS
MATERIALS
MICROSCOPES
ORNL
OXIDES
PERMITTIVITY
PEROVSKITES
PROBES
QUANTUM WELLS
RARE EARTHS
REDUCTION
RESOLUTION
SCANNING ELECTRON MICROSCOPY
SEGREGATION
SENSITIVITY
SIGNAL-TO-NOISE RATIO
SIZE
THICKNESS
TRANSMISSION ELECTRON MICROSCOPY