Structure and Chemistry across Interfaces at Nanoscale of a Ge Quantum Well Embedded within Rare Earth Oxide Layers

2011 ◽  
Vol 17 (5) ◽  
pp. 759-765 ◽  
Author(s):  
Tanmay Das ◽  
Somnath Bhattacharyya
Keyword(s):  
Rare Earth ◽  
Solid Phase ◽  
Rare Earth Oxide ◽  
Dark Field ◽  
X Ray ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Annular Dark Field ◽  
Electron Energy Loss ◽  
Field Imaging

AbstractStructure and chemistry across the rare earth oxide-Ge interfaces of a Gd2O3-Ge-Gd2O3 heterostructure grown on p-Si (111) substrate using encapsulated solid phase epitaxy method have been studied at nanoscale using various transmission electron microscopy methods. The structure across both the interfaces was investigated using reconstructed phase and amplitude at exit plane. Chemistry across the interfaces was explored using elemental mapping, high-angle annular dark-field imaging, electron energy loss spectroscopy, and energy dispersive X-ray spectrometry. Results demonstrate the structural and chemical abruptness of both the interfaces, which is most essential to maintain the desired quantum barrier structure.

3d Reconstruction of Sub-Nm Beam Profiles in STEM

2001 ◽  
Vol 7 (S2) ◽  
pp. 344-345
Author(s):  
G. Möbus ◽  
R.E. Dunin-Borkowski ◽  
C.J.D. Hethėrington ◽  
J.L. Hutchison
Keyword(s):  
Electron Beam ◽  
Chemical Analysis ◽  
Energy Loss ◽  
Intensity Distribution ◽  
Dark Field ◽  
Beam Forming ◽  
Dark Field Imaging ◽  
Annular Dark Field ◽  
Electron Energy Loss ◽  
Field Imaging

Introduction:Atomically resolved chemical analysis using techniques such as electron energy loss spectroscopy and annular dark field imaging relies on the ability to form a well-characterised sub-nm electron beam in a FEGTEM/STEM [1-2]. to understand EELS+EDX-signal formation upon propagation of a sub-nm beam through materials we first have to assess precisely the beam intensity distribution in vacuum and find conditions for the best obtainable resolution.Experimental Details:Modern TEM/STEM instruments combine features of both imaging and scanning technology. The beam forming capability approaches closely that for dedicated STEMs, while CCD recording devices allow us to measure the beam profile by direct imaging at magnifications up to 1.5 M. The recording of a “z-section” series through the 3D intensity distribution of the cross-over can therefore be realised by recording of a “condenser focal series”.

scholarly journals Annular Dark Field Imaging of Catalyst Nanoparticles in Single Shot Dynamic Transmission Electron Microscopy

2009 ◽  
Vol 15 (S2) ◽  
pp. 1082-1083
Author(s):  
D Masiel ◽  
B Reed ◽  
T LaGrange ◽  
ND Browning
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dark Field ◽  
Single Shot ◽  
Catalyst Nanoparticles ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Annular Dark Field ◽  
Field Imaging

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Atomic-Scale Imaging of Dopant Atom Distributions Within Silicon δ-Doped Layers

1999 ◽  
Vol 589 ◽  
Author(s):  
R. Vanfleet ◽  
D.A. Muller ◽  
H.J. Gossmann ◽  
P.H. Citrin ◽  
J. Silcox
Keyword(s):  
Dark Field ◽  
Atomic Scale ◽  
Dopant Atom ◽  
Specimen Preparation ◽  
Dark Field Imaging ◽  
Dramatic Difference ◽  
Annular Dark Field ◽  
Dopant Atoms ◽  
Electron Energy Loss ◽  
Field Imaging

AbstractWe report measurements of the distribution of Sb atoms in σ-doped Si, over a wide 2-D concentration range. Both annular dark-field imaging and electron energy loss spectroscopy proved sufficiently sensitive to locate Sb atoms at the atomic scale. Improvements in both detector sensitivities and specimen preparation were necessary to achieve these results, which offer a surprising explanation for the dramatic difference in electrical activity between 2-D and 3-D dopant distributions at the same effective volume concentrations. The prospects for the general identification of individual dopant atoms will be discussed.

Identification of Ferrous-Ferric Fe3O4 Nanoparticles in Recombinant Human Ferritin Cages

2013 ◽  
Vol 19 (4) ◽  
pp. 835-841 ◽  
Author(s):  
Michael G. Walls ◽  
Changqian Cao ◽  
Kui Yu-Zhang ◽  
Jinhua Li ◽  
Renchao Che ◽  
...  
Keyword(s):  
Dark Field ◽  
Standard Data ◽  
Preparation Conditions ◽  
Dark Field Imaging ◽  
Annular Dark Field ◽  
Human Ferritin ◽  
Quantitative Manner ◽  
Atom Counting ◽  
Electron Energy Loss ◽  
Field Imaging

AbstractRecombinant ferritin is an excellent template for the synthesis of magnetic nanoparticles. This paper describes carefully performed experiments both to identify ironoxides within nanoparticles and to measure the number of iron atoms in the cores of recombinant human H-chain ferritin (HFn), based on spectroscopy techniques. Using electron energy-loss spectroscopy (EELS) analysis, magnetite (Fe3O4) has been unequivocally identified as the ironoxide formed within HFn cores under special preparation conditions. Atom counting analysis by EELS and high-angle annular dark-field imaging further allowed the correlation of the particle sizes to the real Fe atom numbers in a quantitative manner. These results help clarify some structural confusion between magnetite and maghemite (γ-Fe2O3), and also provide standard data for the number of Fe atoms within Fe3O4 particles of a given size, whose use is not limited to cases of magnetite synthesized in the cores of recombinant human ferritin.

Complex Metallic Alloys – Microstructure Characterization

2013 ◽  
Vol 592-593 ◽  
pp. 483-488
Author(s):  
Jozef Janovec ◽  
Ivona Černičková ◽  
Pavol Priputen
Keyword(s):  
Electron Microscopy ◽  
Dark Field ◽  
Metallic Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Annular Dark Field ◽  
Points Of View ◽  
Complex Metallic Alloys

The recent findings related to binary and ternary structurally complex phases in selected complex metallic alloys coming under Al-Pd-Co, Al-Cu-Co, and Al-Mn-Fe systems are presented. The phases were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, high-angle annular dark-field imaging, X-ray diffraction, and differential thermal analysis. There are highlighted some unusual features of phases D, U, T, and ε-family from both structural and compositional points of view.

Environmental Optimization for Sub-0.2NM Scanning Transmission Electron Microscopy

2000 ◽  
Vol 6 (S2) ◽  
pp. 110-111
Author(s):  
D. A. Muller ◽  
J. Grazul ◽  
F. H. Baumann ◽  
R. Hynes ◽  
T. L. Hoffman
Keyword(s):  
Electromagnetic Interference ◽  
Dark Field ◽  
Limiting Factors ◽  
Scanning System ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Electrical Loads ◽  
Field Imaging

Sub-0.2 nm probes can now be readily obtained on Schottky field-emission microscopes[1]. However environmental instabilities are proving to be the limiting factors for atomic resolution spectroscopy and distortion-free annular-dark field imaging, as a result of the long acquisition times (comparable to those required for inline holography[2]), and from the serial nature of the scanning system where instabilities result in image distortions rather than reductions in contrast. Troubleshooting the two most common environmental problems are discussed here.Electromagnetic interference can cause beam deflections in both the scanning system and the spectrometer [3](< 0.3 mG r.ms for 0.3nm, < 0.2 mG for 0.2 nm). These are most easily dealt with before the machine is installed, as substantial rewiring may be necessary. There is little that can be done about quasi-DC fields, such as from elevators and nearby trains and buses. Major sources of AC electromagnetic interference are unbalanced electrical loads.

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