Atomic structure of CdTe dislocations studied by HREM

1989 ◽  
Vol 47 ◽  
pp. 576-577
Author(s):  
P. Lu ◽  
R.W. Glaisher ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Ion Beam ◽  
High Resolution Electron Microscopy ◽  
Resolution Limit ◽  
The Core ◽  
Partial Dislocations ◽  
Resolution Electron ◽  
Argon Ion ◽  
Image Simulations

The determination of the atomic core of dislocations in semiconductors is a challenging problem for high-resolution electron microscopy(HREM). In previous studies, various defects in elemental semiconductors, III-V and II-VI compound semiconductors have been reported. In particular, the core structure of the 30° partial dislocations in silicon, which are dissociated from a perfect 60° dislocation, have been deduced. present study, various CdTe dislocations have been imaged at 400keV. and their core structures have been analyzed with assistance from multi-slice image simulations. Sections of CdTe single crystal were cut normal to the [110] direction, followed by mechanically polishing to a thickness of ˜ 20 microns and finally argon ion-beam milling to perforation for electron microscopy. The crystals were examined with a JEM-4000EX. having a structure resolution limit of ˜ 1.7Å at 400keV.

Limits for high-resolution electron microscopy of inorganic materials?

1987 ◽  
Vol 45 ◽  
pp. 4-5
Author(s):  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Spherical Aberration ◽  
High Resolution Electron Microscopy ◽  
Inorganic Materials ◽  
Atomic Scale ◽  
Resolution Limit ◽  
Contrast Transfer Function ◽  
Existing Problems ◽  
Resolution Electron ◽  
Electron Microscopes

The era of atomic-resolution electron microscopy has finally arrived. In virtually all inorganic materials, including oxides, metals, semiconductors and ceramics, it is possible to image individual atomic columns in low-index zone-axis projections. A whole host of important materials’ problems involving defects and departures from nonstoichiometry on the atomic scale are waiting to be tackled by the new generation of intermediate voltage (300-400keV) electron microscopes. In this review, some existing problems and limitations associated with imaging inorganic materials are briefly discussed. The more immediate problems encountered with organic and biological materials are considered elsewhere.Microscope resolution. It is less than a decade since the state-of-the-art, commercially available TEM was a 200kV instrument with a spherical aberration coefficient of 1.2mm, and an interpretable resolution limit (ie. first zero crossover of the contrast transfer function) of 2.5A.

Atomic chemistry by HREM and image simulations?

1986 ◽  
Vol 44 ◽  
pp. 828-829
Author(s):  
J.M. Howe ◽  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron ◽  
Image Simulations

The technique of high-resolution electron microscopy (HREM) is invaluable to the materials scientist because it allows examination of microstructural features at levels of resolution that are unobtainable by most other methods. Although the structural information which can be determined by HREM and accompanying image simulations has been well documented in the literature, there have only been a few cases where this technique has been used to reveal the chemistry of individual columns or planes of atoms, as occur in segregated and ordered materials.

Silicon-Sapphire Interface: A High Resolution Electron Microscopy Study

1980 ◽  
Vol 2 ◽  
Author(s):  
Fernando A. Ponce
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Silicon Layer ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Resolution Limit ◽  
High Concentration ◽  
Transmission Electron ◽  
Resolution Electron

ABSTRACTThe structure of the silicon-sapphire interface of CVD silicon on a (1102) sapphire substrate has been studied in crøss section by high resolution transmission electron microscopy. Multibeam images of the interface region have been obtained where both the silicon and sapphire lattices are directly resolved. The interface is observed to be planar and abrupt to the instrument resolution limit of 3 Å. No interfacial phase is evident. Defects are inhomogeneously distributed at the interface: relatively defect-free regions are observed in the silicon layer in addition to regions with high concentration of defects.

Structure, Composition and Stability of Heterophase Boundaries

1997 ◽  
Vol 3 (S2) ◽  
pp. 673-674
Author(s):  
M. Rühle ◽  
T. Wagner ◽  
S. Bernath ◽  
J. Plitzko ◽  
C. Scheu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Elevated Temperatures ◽  
Analytical Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Advanced Materials ◽  
Bulk Crystals ◽  
Transmission Electron ◽  
Resolution Electron ◽  
The Stability

Heterophase boundaries play an important role in advanced materials since those materials often comprise different components. The properties of the materials depend strongly on the properties of the interface between the components. Thus, it is important to investigate the stability of the microstructure with respect to annealing at elevated temperatures. In this paper results will be presented on the structure and composition of the interfaces between Cu and (α -Al2O3. The interfaces were processed either by growing a thin Cu overlayer on α- Al2O3 in a molecular beam epitaxy (MBE) system or by diffusion bonding bulk crystals of the two constituents in an UHV chamber. To improve the adhesion of Cu to α -Al2O3 ultrathin Ti interlayers were deposited between Cu and α - Al2O3.Interfaces were characterized by different transmission electron microscopy (TEM) techniques. Quantitative high-resolution electron microscopy (QHRTEM) allows the determination of the structure (coordinates of atoms) while analytical electron microscopy (AEM) allows the determination of the composition with high spatial resolution.

Trends in Atomic Resolution Electron Microscopy

1994 ◽  
Vol 332 ◽  
Author(s):  
David J. Smith ◽  
M.R. Mccartney
Keyword(s):  
Electron Microscopy ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Operating Conditions ◽  
Atomic Scale ◽  
Irradiation Damage ◽  
Image Recording ◽  
Exit Surface ◽  
Resolution Electron ◽  
Image Simulations

ABSTRACTStructural information on the atomic scale is readily accessible from thin samples using the technique of high-resolution electron microscopy. Electron micrographs recorded under well-defined operating conditions can be directly interpreted in terms of atomic arrangements around defects of interest such as dislocations and interfaces. Digital image recording with slow-scan CCD cameras and quantitative comparisons with image simulations based on structural models are starting to lead to improved accuracy and reliability in structure determinations. Techniques based upon holographic methods are utilizing the superior illumination coherence of the field emission electron source to enhance resolution beyond the conventional extended Scherzer limit. Innovative methods for combining image and diffraction pattern information are also leading to improved levels of resolution for periodic objects. Care is needed to ensure that electron irradiation damage and surface cleanliness do not impose unnecessary restrictions on the details that can be extracted from recorded micrographs. It is proposed that the complex wavefunction emerging from the exit-surface of the sample should be considered as a basis for comparing the differences between experimental micrographs and image simulations.

Sign in / Sign up

Export Citation Format

Share Document