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.

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.

Asymmetric Cracking in Znse/ZnSxSel−x Superlattices Grown by Molecular Bean Epitaxy

1987 ◽  
Vol 102 ◽  
Author(s):  
Richard J. Dalby ◽  
John Petruzzello
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Expansion ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Lattice Mismatch ◽  
Sulfur Concentration ◽  
Transmission Electron ◽  
Theoretical Predictions ◽  
Superlattice Layer

ABSTRACTOptical and transmission electron microscopy have been used to study cracks appearing in ZnSe/ZnSxSe1−x (x ∼ 0.38) superlattices grown by Molecular Beam Epitaxy. It Is shown that when a fracture occurs it is confined, in most cases, to the superlattice and propagates along <011> cleavage directions in these <001> oriented epilayers. Cracks were not observed in all superlattices and their onset is discussed in relation to sulfur concentration, overall superlattice height, individual superlattice layer thicknesses, and stress, tensile or compressive, due to lattice mismatch and thermal expansion differences between buffer layer and superlattice. It was found that by adjusting the controllable parameters, cracks in the superlattices could be eliminated. Orientation and density of these features have been related to asynnmetric cracking associated with the zincblende structure of these II-VI materials. Experimental results are shown to be in agreement with theoretical predictions of critical heights for the onset of cracking.

Transmission electron microscopy of GaN columnar nanostructures grown by molecular beam epitaxy

2001 ◽  
Vol 43 (1) ◽  
pp. 151-156 ◽  
Author(s):  
V. V. Mamutin ◽  
N. A. Cherkashin ◽  
V. A. Vekshin ◽  
V. N. Zhmerik ◽  
S. V. Ivanov
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Transmission Electron

A Study of the Defect Structure in GaAS1−xPx/GaAs AS x<0.25

1993 ◽  
Vol 317 ◽  
Author(s):  
G. Aragon ◽  
M.J. De Castro ◽  
S.I. Molina ◽  
Y. Gonzalez ◽  
L. Gonzalez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam Epitaxy ◽  
Defect Structure ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Atomic Layer ◽  
Multiple Cracks ◽  
Transmission Electron ◽  
Phosphorous Content

ABSTRACTThe defect structure of GaAsP layer grown by Atomic Layer Molecular Beam Epitaxy on (001) GaAs substrate has been studied by Transmission Electron Microscopy. The phosphorous content and the epilayer thickness have been changed below 25% and 1μm respectively. Three kinds of defect structure have been found: a) α-δ fringes at the interface for coherent epilayer, b) Misfit dislocation for thin epilayers and c) Multiple cracks normal to the interface and parallel to one <110> direction for thick epilayers.

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.

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