| Autor: |
Yasin FS; Department of Physics , 1274 University of Oregon , Eugene , Oregon 97403 , United States., Harvey TR; Department of Physics , 1274 University of Oregon , Eugene , Oregon 97403 , United States.; IV. Physicalisches Insitut , Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1 , 37077 Göttingen , Germany., Chess JJ; Department of Physics , 1274 University of Oregon , Eugene , Oregon 97403 , United States., Pierce JS; Department of Physics , 1274 University of Oregon , Eugene , Oregon 97403 , United States., Ophus C; National Center for Electron Microscopy , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States., Ercius P; National Center for Electron Microscopy , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States., McMorran BJ; Department of Physics , 1274 University of Oregon , Eugene , Oregon 97403 , United States. |
| Abstrakt: |
Atomic resolution imaging of light elements in electron-transparent materials has long been a challenge. Biomolecular materials, for example, are rapidly altered by incident electrons. We demonstrate a scanning transmission electron microscopy (STEM) technique, called STEM holography, capable of efficient structural analysis of beam-sensitive nanomaterials. STEM holography measures the absolute phase and amplitude of electrons passed through a specimen via interference with a vacuum reference wave. We use an amplitude-dividing nanofabricated grating to prepare multiple beams focused at the sample. We configure the postspecimen microscope imaging system to overlap the beams, forming an interference pattern. We record and analyze the pattern at each 2D-raster-scan-position, reconstructing the complex object wave. As a demonstration, we image gold nanoparticles on an amorphous carbon substrate at 2.4 Å resolution. STEM holography offers higher contrast of the carbon while maintaining gold atomic lattice resolution compared to high angle annular dark field STEM. |
