Identification of site-specific isotopic labels by vibrational spectroscopy in the electron microscope

Science ◽  
2019 ◽  
Vol 363 (6426) ◽  
pp. 525-528 ◽  
Author(s):  
Jordan A. Hachtel ◽  
Jingsong Huang ◽  
Ilja Popovs ◽  
Santa Jansone-Popova ◽  
Jong K. Keum ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Spatial Resolution ◽  
Theoretical Calculations ◽  
Scanning Transmission Electron Microscope ◽  
Real Space ◽  
Site Specific ◽  
Spatially Resolved ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Isotopic Labels

The identification of isotopic labels by conventional macroscopic techniques lacks spatial resolution and requires relatively large quantities of material for measurements. We recorded the vibrational spectra of an α amino acid, l-alanine, with damage-free “aloof” electron energy-loss spectroscopy in a scanning transmission electron microscope to directly resolve carbon-site–specific isotopic labels in real space with nanoscale spatial resolution. An isotopic red shift of 4.8 ± 0.4 milli–electron volts in C–O asymmetric stretching modes was observed for 13C-labeled l-alanine at the carboxylate carbon site, which was confirmed by macroscopic infrared spectroscopy and theoretical calculations. The accurate measurement of this shift opens the door to nondestructive, site-specific, spatially resolved identification of isotopically labeled molecules with the electron microscope.

Attainment of 40.5 pm spatial resolution using 300 kV scanning transmission electron microscope equipped with fifth-order aberration corrector

Microscopy ◽  
2017 ◽  
Vol 67 (1) ◽  
pp. 46-50
Author(s):  
Shigeyuki Morishita ◽  
Ryo Ishikawa ◽  
Yuji Kohno ◽  
Hidetaka Sawada ◽  
Naoya Shibata ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Spatial Resolution ◽  
Transmission Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Technological Developments ◽  
Resolution Imaging ◽  
Fifth Order

Abstract The achievement of a fine electron probe for high-resolution imaging in scanning transmission electron microscopy requires technological developments, especially in electron optics. For this purpose, we developed a microscope with a fifth-order aberration corrector that operates at 300 kV. The contrast flat region in an experimental Ronchigram, which indicates the aberration-free angle, was expanded to 70 mrad. By using a probe with convergence angle of 40 mrad in the scanning transmission electron microscope at 300 kV, we attained the spatial resolution of 40.5 pm, which is the projected interatomic distance between Ga–Ga atomic columns of GaN observed along [212] direction.

Highly spatially resolved Cathodoluminescence of Single GaN Quantum Dots directly performed in a Scanning Transmission Electron Microscope

2012 ◽  
Vol 18 (S2) ◽  
pp. 1878-1879 ◽  
Author(s):  
G. Schmidt ◽  
M. Müller ◽  
F. Bertram ◽  
P. Veit ◽  
S. Petzold ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
Scanning Transmission Electron ◽  
Spatially Resolved ◽  
Transmission Electron ◽  
Scanning Transmission

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Measuring Polymer Microstructure using Spatially-Resolved Eels in the Stem

1996 ◽  
Vol 461 ◽  
Author(s):  
K. Siangchaew ◽  
D. Arayasantiparb ◽  
M. Libera
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Heavy Element ◽  
Large Data ◽  
Scanning Transmission Electron Microscope ◽  
Differential Staining ◽  
Spatially Resolved ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Spectrum Imaging

ABSTRACTImage contrast for the examination of multiphase polymers in the transmission electron microscope (TEM) usually requires differential staining by a heavy element (Os, Ru, U). Staining methods have provided a wealth of microstructural information in polymers, but there are situations, particularly where high resolution is needed, where staining is undesirable or impossible. This research has collected microstructural information from multiphase polymers without heavy-element stains using spatially-resolved electron energy-loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM). The technique is known as spectrum imaging. The principal problems facing spectrum imaging in polymer applications are: (1) the identification of spectral fingerprints distinguishing different polymer phases; and (2) the extraction of meaningful microstructural data from large data sets where the signal is weak due to instrumentation and materials constraints. This paper describes applications of spectrum imaging to PE/PS and HDPE/Nylon 6 blends. The aim is to identify adequate spectral features and establish data acquisition and extraction procedures for applications to general, unstained, multiphase polymers.

Preliminary Results from the First Monochromated and Aberration Corrected 200-kV Field-Emission Scanning Transmission Electron Microscope

2006 ◽  
Vol 12 (6) ◽  
pp. 498-505 ◽  
Author(s):  
Thomas Walther ◽  
Heiko Stegmann
Keyword(s):  
Electron Microscope ◽  
Spatial Resolution ◽  
Transmission Electron Microscope ◽  
Chromatic Aberration ◽  
Beam Current ◽  
Scanning Transmission Electron Microscope ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Aberration Corrected

Experimental results from the first monochromated and aberration-corrected scanning transmission electron microscope operated at 200 kV are described. The formation of an electron probe with a diameter of less than 0.2 nm at an energy width significantly under 0.3 eV and its planned application to the chemical analysis of nanometer-scale structures in materials science are described. Both energy and spatial resolution will benefit from this: The monochromator improves the energy resolution for studies of energy loss near edge structures. The Cs corrector allows formation of either a smaller probe for a given beam current or yields, at fixed probe size, an enhanced beam current density using a larger condenser aperture. We also point out another advantage of the combination of both components: Increasing the convergence angle by using larger condenser apertures in an aberration-corrected instrument will enlarge the undesirable chromatic focus spread. This in turn influences spatial resolution. The effect of polychromatic probe tails is proportional to the product of convergence angle, chromatic aberration constant, and energy spread. It can thus be compensated for in our new instrument by decreasing the energy width by the same factor as the beam convergence is increased to form a more intense probe. An alternative in future developments might be hardware correction of the chromatic aberration, which could eliminate the chromatic probe spread completely.

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