Interlayer mixing in GaAs/AlxGa1-xAs heterostructures as a result of Se+ ion implantation

1988 ◽  
Vol 46 ◽  
pp. 908-909
Author(s):  
E.G. Bithell ◽  
W.M. Stobbs
Keyword(s):  
Ion Implantation ◽  
Diffusion Coefficients ◽  
Dark Field ◽  
Atomic Mass ◽  
Composition Profile ◽  
Semiconductor Heterostructures ◽  
Transmission Electron ◽  
Microscope Images ◽  
Damage Process ◽  
Electron Energy Loss

It is well known that the microstructural consequences of the ion implantation of semiconductor heterostructures can be severe: amorphisation of the damaged region is possible, and layer intermixing can result both from the original damage process and from the enhancement of the diffusion coefficients for the constituents of the original composition profile. A very large number of variables are involved (the atomic mass of the target, the mass and energy of the implant species, the flux and the total dose, the substrate temperature etc.) so that experimental data are needed despite the existence of relatively well developed models for the implantation process. A major difficulty is that conventional techniques (e.g. electron energy loss spectroscopy) have inadequate resolution for the quantification of any changes in the composition profile of fine scale multilayers. However we have demonstrated that the measurement of 002 dark field intensities in transmission electron microscope images of GaAs / AlxGa1_xAs heterostructures can allow the measurement of the local Al / Ga ratio.

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.

Electron Irradiation and Electron Tomography Studies of Glasses and Glass Nanocomposites

2008 ◽  
Vol 1107 ◽  
Author(s):  
G. Möbus ◽  
G. Yang ◽  
Z. Saghi ◽  
X. Xu ◽  
R.J. Hand ◽  
...  
Keyword(s):  
Fine Structure ◽  
Electron Tomography ◽  
Dark Field ◽  
Gradual Transition ◽  
Borosilicate Glasses ◽  
Redox Partner ◽  
Transmission Electron ◽  
Annular Dark Field ◽  
Microscopy Techniques ◽  
Electron Energy Loss

AbstractCharacterization of glasses and glass nanocomposites using modern transmission electron microscopy techniques is demonstrated. Techniques used include: (i) high-angle-annular dark field STEM for imaging of nanocomposites, (ii) electron tomography for 3D reconstruction and quantification of nanoparticle volume fractions, and (iii) fine structure electron energy loss spectroscopy for evaluation of boron coordination. Precipitation of CeO2nanoparticles in borosilicate glasses is examined as a function of glass composition and redox partner elements. A large increase in the solubility of Ce is found for compositions where Ce retains +IV valence in the glass. Irradiation experiments with electrons and λ-rays are summarized and the degree of damage is compared by using changes in the boron K-edge fine structure, which allows the gradual transition from BO4to BO3coordination to be followed.

Atomic Ordering and Disordering of Amorphous CoNiP Alloy

2018 ◽  
Vol 386 ◽  
pp. 377-382
Author(s):  
Evgenii V. Pustovalov ◽  
Alexander F. Fedorets ◽  
Vladimir V. Tkachev ◽  
Vladimir S. Plotnikov
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Dark Field ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Electron Energy Loss ◽  
Temperature Heating ◽  
Thermal Stability Of

The structure of electrolytically deposited nanocrystalline alloys of the CoP-CoNiP systems under low-temperature heating was investigated by means of high-resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF STEM), and analytical methods such as energy dispersive x-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS). Structural relaxation and crystallization were investigated at temperatures from 150°C to 300°C. Structural and compositional inhomogeneities were found in the CoP-CoNiP alloys, while the local changes in composition were found to reach 15 at.%. Nanocrystals in the alloys grew most intensely in the presence of a free surface. It was determined that the local diffusion coefficient ranged from 1.2 to 2.4 10−18 m2/s, which could be explained by the surface diffusion prevalence. The data gathered in these investigations can be further used to predict the thermal stability of CoP-CoNiP alloys.

scholarly journals FEI Titan G2 80-200 CREWLEY

2016 ◽  
Vol 2 ◽  
Author(s):  
András Kovács ◽  
Roland Schierholz ◽  
Karsten Tillmann
Keyword(s):  
Dark Field ◽  
Electron Gun ◽  
Atomic Scale ◽  
Fourth Generation ◽  
High Brightness ◽  
Transmission Electron ◽  
Wide Range ◽  
Schottky Type ◽  
Technical Specifications ◽  
Electron Energy Loss

<p>The FEI Titan G2 80-200 CREWLEY is a fourth generation transmission electron microscope which has been specifically designed for the investigation of a wide range of solid state phenomena taking place on the atomic scale of both the structure and chemical composition. For these purposes, the FEI Titan G2 80-200 CREWLEY is equipped with a Schottky type high-brightness electron gun (FEI X-FEG), a Cs probe corrector (CEOS DCOR), an in-column Super-X energy dispersive X-ray spectros-copy (EDX) unit (ChemiSTEM technology), a post-column energy filter system (Gatan Enfinium ER 977) with dual electron energy-loss spectroscopy (EELS) option allowing a simultaneous read-out of EDX and EELS signals at a speed of 1000 spectra per second. For data recording the microscope is equipped with an angular dark-field (ADF) scanning TEM (STEM) detector (Fischione Model 3000), on-axis triple BF, DF1, DF2 detectors, on-axis BF/DF Gatan detectors as well as a 4 megapixel CCD system (Gatan UltraScan 1000 XP-P). Typical examples of use and technical specifications for the instrument are given below.</p>

A Technique for Displaying Theoretical Transmission Electron Microscope Images

1971 ◽  
Vol 29 ◽  
pp. 96-97
Author(s):  
P. J. Fillingham ◽  
H. J. Leamy ◽  
D. M. Maher
Keyword(s):  
Electron Microscope ◽  
Magnetic Tape ◽  
Dark Field Image ◽  
Diffraction Theory ◽  
Dark Field ◽  
Transmission Electron ◽  
High Quality Image ◽  
Microscope Images ◽  
Analog Form ◽  
Theoretical Intensity

Since the earliest work on computer simulation of electron microscope images, it has been realized that a technique for producing a high quality image would facilitate analysis of the information content of theoretical intensity data. In particular, this would be an aid in image analysis and testing approximations used in electron diffraction theory.A technique has been developed for producing a semiglossy print from data on magnetic tape using a commercial facsimile device. In the present application only the receiver of the facsimile device is used to produce a simulated electron micrograph. An array of intensities corresponding to the light or dark field image of a defect is computed. A simple two-dimensional interpolation scheme gives an enlarged array (on magnetic tape) which is then converted to analog form and transmitted to the receiver of the facsimile device.

EBIC and EBAC Analysis of Site Specific STEM Samples

2017 ◽  
Author(s):  
C.T. Schamp ◽  
Y. Suzuki ◽  
J. Fuse ◽  
K. Ito ◽  
H. Tanaka ◽  
...  
Keyword(s):  
Electron Beam ◽  
Dark Field ◽  
Primary Electron ◽  
X Rays ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Beam Sample ◽  
Probe Size ◽  
Electron Beam Induced Current ◽  
Electron Energy Loss

Abstract In transmission electron microscopy (TEM), one typically considers bright-field or dark-field imaging signals, which utilize the transmitted and scattered electrons, respectively. Analytical signals such as characteristic X-Rays or primary electron beam energy losses from inelastic scattering events give rise to the energy dispersive X-Ray spectroscopy and electron energy loss spectroscopy techniques, respectively. In this paper, the detection of the electron beam absorbed current (EBAC) and electron beam induced current (EBIC) signals is reported using a specially designed scanning TEM holder and associated amplification electronics. By utilizing thin TEM samples where the beam-sample interaction volume is controlled more through the incident electron probe size, the EBAC and EBIC signal resolution is improved to the point where implant regions and Schottky junction depletion zones can be visualized.

Analytical High-Resolution TEM Study on Au/TiO2 Catalysts

1999 ◽  
Vol 589 ◽  
Author(s):  
T. Akita ◽  
K. Tanaka ◽  
S. Tsubota ◽  
M. Haruta
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
High Resolution Tem ◽  
Electron Energy Loss

AbstractHRTEM(High-Resolution Transmission Electron Microscope), HAADF-STEM (High Angle Annular Dark Field Scanning Transmission Electron Microscope) and EELS(Electron Energy Loss Spectroscopy) techniques were applied for the characterization of Au/TiO2 catalysts. HAADFSTEM provides precise size distributions for Au particles smaller than ∼2nm in diameter. It was observed that many small particles under 2nm were supported on anatase TiO2 having a large surface area. The HAADF-STEM method was examined as a way to measure the shape of Au particles. EELS measurements were also used to examine the interface between Au and TiO2 support to study electronic structure effects.

Microscopic Examination of SiO2/4H-SiC Interfaces

2011 ◽  
Vol 679-680 ◽  
pp. 330-333 ◽  
Author(s):  
Tetsuo Hatakeyama ◽  
Hirofumi Matsuhata ◽  
T. Suzuki ◽  
Takashi Shinohe ◽  
Hajime Okumura
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Dark Field ◽  
Rich Region ◽  
Spatially Resolved ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Electron Energy Loss

SiO2/4H-SiC interfaces are examined by high-resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and spatially resolved electron energy-loss spectroscopy (EELS). HRTEM and HAADF-STEM images of SiO2/4H-SiC interfaces reveal that abrupt interfaces are formed irrespective of the fabrication conditions. Transition regions around the interfaces reported by Zheleva et al. were not observed. Using EELS, profiles of the C/Si and O/Si ratios across an interface were measured. Our measurements did not reveal a C-rich region on the SiC side of the interface, which was reported by Zheleva et al.

TEM Investigation of Nanophase Aluminum Powder

2005 ◽  
Vol 11 (5) ◽  
pp. 410-420 ◽  
Author(s):  
Valéry Y. Gertsman ◽  
Queenie S.M. Kwok
Keyword(s):  
Aluminum Powder ◽  
Dark Field ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Partial Crystallinity ◽  
Large Clusters ◽  
Electron Energy Loss ◽  
Field Imaging ◽  
Good Agreement

Nanophase aluminum powder was characterized in a field-emission-gun transmission electron microscope (TEM). Different techniques were used to investigate the structure of the particles, including conventional bright-field and dark-field imaging, scanning transmission electron microscopy (STEM), high-resolution lattice imaging, diffraction studies, energy dispersive X-ray spectroscopy (EDS) analysis and mapping, and electron energy loss spectroscopy (EELS) analysis and mapping. It has been established that the particle cores consist of aluminum single crystals that sometimes contain crystal lattice defects. The core is covered by a passivating layer of aluminum oxide a few nanometers thick. The alumina is mostly amorphous, but evidences of partial crystallinity of the oxide were also found. The thickness of this layer was measured using different techniques, and the results are in good agreement with each other. The particles are agglomerated in two distinct ways. Some particles were apparently bonded together during processing before oxidation. These mostly form dumbbells covered by a joint oxide layer. Also, oxidized particles are loosely assembled into relatively large clusters.

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