Analysis of High Resolution Electron Microscope Images of the Pd2Si-Si Interface

1981 ◽  
Vol 10 ◽  
Author(s):  
W. Krakow
Keyword(s):  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Dynamical Theory ◽  
Image Features ◽  
Interface Roughness ◽  
Interface Plane ◽  
Resolution Electron ◽  
High Resolution Electron Microscope ◽  
Interface Structures ◽  
Image Detail

High resolution electron micrographs have been obtained from Pd2 Si-Si(111) interfaces viewed edge on and a detailed analysis of the interface structure has been carried out using computer simulations of the images. Since the stacking sequence of hexagonal Pd2Si is AαAαAα..., the question whether the interface plane of Pd2 Si is silicon rich, A, or silicon deficient, α, has been investigated. An advancing interface cannot be planar at all stages of growth; therefore the question of interface roughness along the direction of the electron beam and twinning orientations has been considered. This has been modeled by Fourier shift techniques incorporated into multislice dynamical theory and, of course, is complicated by the dynamical diffraction conditions of the structure and the contributions of high order Bragg reflections to image detail. It has been possible to access the image features present in Pd2 Si/Si micrographs and to point out the difficulties which are encountered not only in this system but in a wide variety of interface structures by high resolution electron microscopy. Perhaps the most important finding of this study is that the interface region contains a mixture of silicon-rich and silicon-deficient Pd2Si planes adjacent to the silicon side of the interface.

Fabrication and characterization - by High Resolution Electron Microscopy and atom probe microanalysis - of Co-based metallic multilayer films

1990 ◽  
Vol 48 (4) ◽  
pp. 772-773
Author(s):  
Amanda K. Petford-Long ◽  
A. Cerezo ◽  
M.G. Hetherington
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Atom Probe ◽  
Multilayer Films ◽  
Interface Roughness ◽  
Probe Field ◽  
Resolution Electron ◽  
Potential Applications ◽  
Field Ion Microscope

The fabrication of multilayer films (MLF) with layer thicknesses down to one monolayer has led to the development of materials with unique properties not found in bulk materials. The properties of interest depend critically on the structure and composition of the films, with the interfacial regions between the layers being of particular importance. There are a number of magnetic MLF systems based on Co, several of which have potential applications as perpendicular magnetic (e.g Co/Cr) or magneto-optic (e.g. Co/Pt) recording media. Of particular concern are the effects of parameters such as crystallographic texture and interface roughness, which are determined by the fabrication conditions, on magnetic properties and structure.In this study we have fabricated Co-based MLF by UHV thermal evaporation in the prechamber of an atom probe field-ion microscope (AP). The multilayers were deposited simultaneously onto cobalt field-ion specimens (for AP and position-sensitive atom probe (POSAP) microanalysis without exposure to atmosphere) and onto the flat (001) surface of oxidised silicon wafers (for subsequent study in cross-section using high-resolution electron microscopy (HREM) in a JEOL 4000EX. Deposi-tion was from W filaments loaded with material in the form of wire (Co, Fe, Ni, Pt and Au) or flakes (Cr). The base pressure in the chamber was around 8×10−8 torr during deposition with a typical deposition rate of 0.05 - 0.2nm/s.

HIGH RESOLUTION ELECTRON MICROSCOPE STUDY OF CdTe-Cd0.6Mn0.4 Te SUPERLATTICES

1985 ◽  
Vol 56 ◽  
Author(s):  
C. CHOI ◽  
N. OTSUKA ◽  
L. A. KOLODZIEJSKI ◽  
R. L. GUNSHOR-a
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Phase Contrast ◽  
Electron Microscope Study ◽  
Lattice Mismatch ◽  
Thick Layer ◽  
High Resolution Electron Microscopy ◽  
Misfit Dislocations ◽  
Resolution Electron ◽  
High Resolution Electron Microscope

AbstractStructures of CdTe-Cd0.6Mn0.4Te superlattices which are caused by the lattice mismatch between suterlattice layers have been studied by high resolution electron microscopy (HREM). In thin-layer superlattices, the crystal lattice in each layeris elastically distorted, resulting in the change of the crystal symmetry from cubic to rhombohedral. The presence of the small rhombohedral distrotion has been confirmed through a phase contrast effect in HREM images. In a thick-layer superlattice, the lattice mismatch is accommodated by dissociated misfit dislocations. Burgers vectors of partial misfit dislocations have been identified from the shift of lattice fringes in HREM images.

Observation of the CdTe-GaAs Interface by High Resolution Electron Microscopy

1984 ◽  
Vol 37 ◽  
Author(s):  
N. Otsuka ◽  
L. A. Kolodziejski ◽  
R. L. Gunshor ◽  
S. Datta ◽  
R. N. Bicknell ◽  
...  
Keyword(s):  
High Resolution ◽  
Film Growth ◽  
Substrate Surface ◽  
High Resolution Electron Microscopy ◽  
Gaas Substrates ◽  
Resolution Electron ◽  
Interfacial Structures ◽  
Substrate Preheating ◽  
High Resolution Electron Microscope

AbstractCdTe films have been grown on GaAs substrates with two types of interfaces - one with the epitaxial relation (111)CdTe║ (100)GaAs and the other with (100)CdTe║ (100)GaAs,. High resolution electron microscope observation of the two types of interfaces was carried out in order to determine the role of the substrate surface microstructure in determining the epitaxy. The interface of the former type shows a direct contact between the CdTe and GaAs crystals, while the interface of the latter type has a very thin oxide layer (∼10 Å in thickness) between the two crystals. These observations suggest that details of the substrate preheating cycle prior to film growth is the principle factor in determining which epitaxial relation occurs in this system. The relation between interfacial structures and the origin of the two epitaxial relations is discussed.

The ultrastructure of coccoliths from the marine alga Emiliania huxleyi (Lohmann) Hay and Mohler: an ultra-high resolution electron microscope study

1983 ◽  
Vol 219 (1215) ◽  
pp. 111-117 ◽  
Keyword(s):  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Emiliania Huxleyi ◽  
Growth Patterns ◽  
Lattice Image ◽  
Nucleation Sites ◽  
Resolution Electron ◽  
Lattice Images ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns

The calcite coccoliths from the alga Emiliania huxleyi (Lohmann) Hay and Mohler have been studied by ultra-high resolution electron microscopy. This paper describes the two different types of structure observed, one in the upper elements, the other in the basal plate, or lower element. The former consisted of small, microdomain structures of 300-500 Å (1 Å = 10 -10 m) in length with no strong orientation. At places along these elements, and particularly in the junction between stem and head pieces, triangular patterns of lattice fringes were observed indicating multiple nucleation sites in the structure. In contrast, the lower element consisted of a very thin single crystalline sheet of calcite which could be resolved into a two dimensional lattice image, shown by a computer program that is capable of simulating electron diffraction patterns and lattice images to be a [421] zone of calcite. A possible mechanism for these growth patterns in the formation of coccoliths is discussed, together with the relevance of such mechanisms to biomineralization generally.

Atomic Level Investigations of W-Si Multilayers by High Resolution Tem and X Ray Scattering

1987 ◽  
Vol 103 ◽  
Author(s):  
S. R Nutt ◽  
J. E. Keem
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Interface Roughness ◽  
Bilayer Thickness ◽  
Individual Layer ◽  
X Ray ◽  
X Ray Scattering ◽  
Resolution Electron ◽  
Ray Scattering

ABSTRACTWe have prepared multilayer films of W-Si with bilayer repeat spacing from approximately 1.5 nm to 9 nm and performed high resolution electron microscopy and low angle x-ray scattering on them. Average composition estimates as inferred from deposition conditions, x ray scattering and electron microscopy are compared. Determinations of the individual layer thickness ratios by electron microscopy and x ray scattering vary significantly from expectations as the bilayer thickness approaches 1.5 nm. Layer intermixing to increase as the bilayer thickness decreases. Composition profiles as inferred from the Cuk x ray profile are compared to those inferred from the high resolution electron micrographs. Visual observations from melectron microscopy are presented indicating that the interface roughness is rapidly damped in the W-Si multilayer system. Estimates of the layer uniformity are made from the high resolution images.

Carbon Support Films for High Resolution Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 76-77
Author(s):  
J. Langmore ◽  
J. Wall ◽  
M. Isaacson ◽  
A. V. Crewe
Keyword(s):  
High Resolution ◽  
Quantum Noise ◽  
Carbon Support ◽  
High Resolution Electron Microscopy ◽  
Carbon Films ◽  
Biological Molecules ◽  
Carbon Substrate ◽  
The Third ◽  
Resolution Electron ◽  
High Resolution Electron Microscope

The observation of single atoms and unstained biological molecules in the high resolution electron microscope depends upon the ability to discriminate between the image of the specimen and that of the support film used. This depends upon three characteristics of the film. The quantum noise in the image is equal to the square root of the number of electrons collected which have been scattered from the fi1m. Another type of noise, the “structural” noise, is caused by fluctuations in the film thickness. The third, “high Z” noise, is caused by extraneous atoms of high atomic number present on the film. In order to find the best carbon substrate for our specimens, we have studied the structure of thin (∼5-50 Å) carbon films evaporated onto various crystalline substrates.

The Observation Of Mg)-Al Interface By Hrem and Microdiffraction

1985 ◽  
Vol 43 ◽  
pp. 240-241
Author(s):  
S.Y. Zhang ◽  
J.M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
High Resolution ◽  
Materials Science ◽  
Incident Beam ◽  
High Resolution Electron Microscopy ◽  
Interface Structure ◽  
Resolution Electron ◽  
Powerful Means ◽  
Interface Structures

The combination of high resolution electron microscopy (HREM) and nanodiffraction techniques provided a powerful means for characterizing many of the interface structures which are of fundamental importance in materials science. In this work the interface structure between magnesium oxide and aluminum has been examined by HREM (with JEM-200CX) and nanodiffraction (with HB-5). The interfaces were formed by evaporating Al on freshly prepared cubic MgO smoke crystals under various vacuum conditions, at 10 -4, 10-5 10-6 and 10-7 torr. The Al layers on the MgO (001) surface are about 100Å thick. TEM observations were performed with the incident beam along the MgO [100] direction so that the interface could be revealed clearly. The nanodiffraction patterns were obtained with the electron beam of 15Å diameter parallel to the interface.

Characterization of structural units in tilt grain boundaries

1992 ◽  
Vol 50 (1) ◽  
pp. 120-121
Author(s):  
Stuart McKernan ◽  
C. Barry Carter
Keyword(s):  
High Resolution ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
High Resolution Electron Microscopy ◽  
Boundary Structure ◽  
Structural Units ◽  
Symmetric Tilt ◽  
Resolution Electron ◽  
Special Cases ◽  
High Resolution Electron Microscope

General tilt grain boundaries can be viewed in terms of small structural units of varying complexity. High-resolution electron microscope (HREM) images of these boundaries in many materials show this repetitive similarity of the atomic structure at the boundary plane. The structure of particular grain boundaries has been examined for several special cases and commonly observed configurations include symmetric tilt grain boundaries and asymmetric tilt grain boundaries with one grain having a prominent, low-index facet. Several different configurations of the boundary structure may possibly occur, even in the same grain boundary. There are thus many possible ways to assemble the basic structural units to form a grain boundary. These structural units and their distribution have traditionally been examined by high-resolution electron microscopy. The images of the projection of the atomic columns (or the tunnels between atomic columns) providing a template for constructing “ball-and-stick ” models of the interface.

Characterization of interface structures in nanocrystalline germanium by means of high-resolution electron microscopy and molecular dynamics simulations

1996 ◽  
Vol 211 (3) ◽  
Author(s):  
W. Neumann ◽  
H. Hofmeister ◽  
D. Conrad ◽  
K. Scheerschmidt ◽  
S. Ruvimov
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Vapor Deposition ◽  
High Resolution Electron Microscopy ◽  
Amorphous Thin Films ◽  
Resolution Electron ◽  
Nanocrystalline Particles ◽  
Dynamics Simulations ◽  
Interface Structures

AbstractThe atomic structure of nanocrystalline particles formed by vapor deposition and subsequent annealing of amorphous thin films of germanium was studied by high resolution electron microscopy (HREM). The HREM images revealed a strongly varied multiply twinned structure. In some regions of adjacent twins contrast features were detected which were caused by an overlapping of twin lamellae. It will be shown by HREM contrast simulations that these interface types can be described by Σ = 3

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