High Resolution Transmission Electron Microscopy of PbTe/Pb1-zEuxSeyTe1-v, Heterostructures.

1986 ◽  
Vol 77 ◽  
Author(s):  
L. Salamanca-Young ◽  
D. L. Partin ◽  
J. Heremans ◽  
E. M. Dresselhaus
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam ◽  
Computing Methods ◽  
Misfit Dislocations ◽  
Structural Perfection ◽  
Superlattice Structure ◽  
Transmission Electron ◽  
Simulated Images

ABSTRACTHigh resolution transmission electron microscopy has been used to study the structure of PbTe/Pb1-zEuxSeyTe1-v semiconductor superlattices and heterojunctions grown on BaF2 substrates by molecular beam epitaxy. The objective of this study is to analyze the interface sharpness and the structural perfection of the samples at their interfaces. In the PbTe/Pb1-zEuxSeyTe1-v system, we have observed misfit dislocations and even amorphous regions for high Eu concentrations. We have also observed two directions of growth of the superlattice film. The interface appears to be sharp to approximately three monolayers. A model for the superlattice structure is suggested and used to obtain simulated images using computing methods. The simulated images are compared with those obtained experimentally.

Structural Characterization of Fe3O4–NiO Superlattices Using High-reSolution Transmission Electron Microscopy

1997 ◽  
Vol 12 (8) ◽  
pp. 2143-2151 ◽  
Author(s):  
A. Rečnik ◽  
D. L. Carroll ◽  
K. A. Shaw ◽  
D. M. Lind ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam ◽  
Spin Exchange ◽  
Magnetic Ordering ◽  
Misfit Dislocations ◽  
Transmission Electron ◽  
High Degree

Superlattices of Fe3O4–NiO layers have been studied by high-resolution transmission electron microscopy (HRTEM). These superlattices are grown by oxygen-plasma-assisted molecular-beam epitaxy (MBE) on (001) oriented MgO substrates, and exhibit a high degree of ordering at the interfaces between the interlayers. The lack of misfit dislocations at the Fe3O4–NiO interfaces suggeststhat lattice strain is largely accommodated by changes in the lattice spacing. By quantitative HRTEM analysis of Fe3O4–NiO interfaces, possible atomic models are discussed, having implications in magnetic ordering and spin exchange mechanisms for such interlayer systems.

Vertical self-organization of Ge1−xMnx nanocolumn multilayers grown on Ge(001) substrates

2016 ◽  
Vol 30 (20) ◽  
pp. 1650269 ◽  
Author(s):  
Thi Giang Le ◽  
Minh Tuan Dau
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Elastic Constant ◽  
Structural Properties ◽  
Molecular Beam ◽  
Self Organization ◽  
Transmission Electron ◽  
2D Model

High-resolution transmission electron microscopy (HR-TEM) has been used to investigate the structural properties of GeMn/Ge nanocolumns multilayer samples grown on Ge(001) substrates by means of molecular beam epitaxy (MBE) system. Four bilayers with the spacer thickness in the range between 6 nm and 15 nm and 10 periods of bilayers of Ge[Formula: see text]Mn[Formula: see text]/Ge nanocolumn are presented. A simplified 2D model based on the theory of elastic constant interactions has been used to provide reasonable explanations to the vertical self-organization of GeMn nanocolumns in multilayers.

Double Periodicity Formation in EuTe/PbTe Superlattices

1995 ◽  
Vol 399 ◽  
Author(s):  
M. Shima ◽  
L. Salamanca-Riba ◽  
G. Springholz ◽  
G. Bauer
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period ◽  
Short Period Superlattices

ABSTRACTMolecular beam epitaxy was used to grow EuTe(x)/PbTe(y) short period superlattices with x=1-4 EuTe(111) monolayers alternating with y≈3x PbTe monolayers. The superlattices were characterized by transmission electron microscopy and high resolution x-ray diffraction. Regions with double periodicity were observed coexisting with areas of nominal periodicity. The sample with x=3.5 and y=9, for example, contains regions with double periodicity of x=7 and y=17. X-ray diffraction measurements confirm the formation of the double periodicity in these samples by the appearance of weak satellites in between the satellites of the nominal periodicity. The double periodicity in the superlattice is believed to result from interdiffusion during the growth. A model for this process is presented.

Transmission electron microscopy study of Co/Pd and Co/Au multilayers

1993 ◽  
Vol 8 (5) ◽  
pp. 1019-1027 ◽  
Author(s):  
F. Hakkens ◽  
A. De Veirman ◽  
W. Coene ◽  
Broeder F.J.A. den
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Columnar Structure ◽  
Electron Microscopy Study ◽  
Misfit Dislocations ◽  
Transmission Electron ◽  
Resolution Electron

The structure of Co/Pd and Co/Au (111) multilayers is studied using transmission electron microscopy and high resolution electron microscopy. We focused on microstructure, atomic stacking (especially at the interfaces), and coherency, as these are structural properties that have considerable magnetic effects. A columnar structure with a strong curvature of the multilayer influenced by substrate temperature during growth is observed. High resolution imaging shows numerous steps at the interfaces of the multilayer structure and the presence of misfit dislocations. In bright-field images, periodic contrast fringes are observed at these interfaces as the result of moiré interference. These moiré fringes are used to study the misfit relaxation at the interfaces, whereas electron diffraction gives the average relaxation over the whole layer. Both measurements determined that, for Co/Pd as well as Co/Au multilayers, 80–85% of the misfit is relaxed and 20–15% remains in the form of strain, independent of the Co layer thickness in the regime studied.

Dislocations in SrTiO3 thin films grown on LaAlO3 substrates

2002 ◽  
Vol 17 (12) ◽  
pp. 3117-3126 ◽  
Author(s):  
Y. L. Qin ◽  
C. L. Jia ◽  
K. Urban ◽  
J. H. Hao ◽  
X. X. Xi
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Lattice Mismatch ◽  
Orthogonal Arrays ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Burgers Vector ◽  
Transmission Electron

The dislocation configurations in SrTiO3 thin films grown epitaxially on LaAlO3 (100) substrates were studied by conventional and high-resolution transmission electron microscopy. Misfit dislocations had, in most cases, a Burgers vector a〈100〉 and line directions of 〈100〉 These dislocations constitute orthogonal arrays of parallel dislocations at the interface, relieving the lattice mismatch between SrTiO3 and LaAlO3. Threading dislocations were found to be the major defects in the films. Two types of threading dislocations with the Burgers vectors a〈100〉?and a〈100〉?were identified. The relations of these threading dislocations with the misfit dislocations were investigated and are discussed in this paper.

Gas-source molecular beam epitaxy of monocrystalline β–SiC on vicinal α(6H)–SiC

1993 ◽  
Vol 8 (11) ◽  
pp. 2753-2756 ◽  
Author(s):  
L.B. Rowland ◽  
R.S. Kern ◽  
S. Tanaka ◽  
Robert F. Davis
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Nucleation And Growth ◽  
Epitaxial Films ◽  
Gas Source ◽  
Transmission Electron ◽  
Surface Migration

Single-crystal epitaxial films of cubic β(3C)–SiC(111) have been deposited on hexagonal α(6H)–SiC(0001) substrates oriented 3–4° toward [1120] at 1050–1250 °C via gas-source molecular beam epitaxy using disilane (Si2H6) and ethylene (C2H4). High-resolution transmission electron microscopy revealed that the nucleation and growth of the β(3C)–SiC regions occurred primarily on terraces between closely spaced steps because of reduced rates of surface migration at the low growth temperatures. Double positioning boundaries were observed at the intersections of these regions.

Misfit Dislocations at Mismatched Epitactic Heterojunctions

1990 ◽  
Vol 198 ◽  
Author(s):  
Jane G. Zhu ◽  
C. Barry Carter ◽  
Chris J. Palmstrom
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Antiphase Boundary ◽  
Misfit Dislocations ◽  
Surface Steps ◽  
Transmission Electron ◽  
Different Types ◽  
Significant Factors

ABSTRACTThe formation and structures of misfit dislocations are significant factors in understanding heteroepitaxy of lattice-mismatched materials. In this study, GaAs/Si, CoGa/GaAs and ErAs/GaAs heterojunctions in materials grown by molecular-beam epitaxy have been characterized using transmission electron microscopy. Different types of misfit dislocations have been generated at these interfaces. The different dislocation configurations are discussed, along with interactions between 60° and 90° dislocations in GaAs/Si heterojunctions; the 60° dislocations might be associated with surface steps or edges of islands. The growth of antiphase boundary structures in the CoGa and ErAs grown on GaAs are proposed.

Structures of Nb/Al2O3 Interfaces Produced by Different Experimental Routes

1990 ◽  
Vol 183 ◽  
Author(s):  
J. Mayer ◽  
W. Mader ◽  
D. Knauss ◽  
F. Ernst ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Al Alloy ◽  
Misfit Dislocations ◽  
Orientation Relationships ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Sapphire Substrates ◽  
Transmission Electron

AbstractNb/Al2O3 interfaces were produced by (i) diffusion bonding of single crystalline Nb and Al2O3 at 1973 K, (ii) internal oxidation of a Nb-3at.% Al alloy at 1773 K, and (iii) molecular beam epitaxy (MBE) growth of 500 nm thick Nb overlayers on sapphire substrates at 1123 K. Cross-sectional specimens were prepared and studied by conventional (CTEM) and high resolution transmission electron microscopy (HREM). The orientation relationships between Nb and Al2O3 were identified by diffraction studies. HREM investigations revealed the structures of the different interfaces including the presence of misfit dislocations at or near the interface. The results for the different interfaces are compared.

Sign in / Sign up

Export Citation Format

Share Document