Atomic Structure of HgTe and CdTe Epitaxial Layers Grown by MBE on GaAs Substrates

1986 ◽  
Vol 90 ◽  
Author(s):  
F. A. Ponce ◽  
G. B. Anderson ◽  
J. M. Ballingall
Keyword(s):  
Electron Microscopy ◽  
Atomic Structure ◽  
Molecular Beam ◽  
Atomic Level ◽  
Point Of View ◽  
Defect Structures ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial ◽  
Gaas Substrates ◽  
Transmission Electron

ABSTRACTUsing high resolution transmission electron microscopy (HRTEM) it is possible to directly image the projected structure of semiconductors with point resolutions at the atomic level. This technique has been applied to the study of interface and defect structures associated with molecular beam epitaxial (MBE) growth of HgCdTe layers on GaAs substrates. The structure of the CdTe/GaAs interfaces is described for (100) and (111) epitaxy. From the atomic structure, a model for the early stages of epitaxial growth is presented. The structure of HgTe-CdTe superlattices is discussed from the HRTEM point of view.

A transmission electron microscopy investigation of SiC films grown on Si(111) substrates by solid-source molecular beam epitaxy

1998 ◽  
Vol 13 (12) ◽  
pp. 3571-3579 ◽  
Author(s):  
U. Kaiser ◽  
S. B. Newcomb ◽  
W. M. Stobbs ◽  
M. Adamik ◽  
A. Fissel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Growth Parameters ◽  
Force Microscopy ◽  
Molecular Beam Epitaxial ◽  
Atomic Force ◽  
Transmission Electron ◽  
Microscopy Investigation ◽  
Sic Films

The effects of different growth parameters on the microstructure of the SiC films formed during simultaneous two-source molecular-beam-epitaxial (MBE) deposition have been investigated. Substrate temperatures as low as 750–900 °C have been used. The relationship between a number of different growth morphologies and deposition conditions has been established. The formation of single-crystal 3C films has been found to occur at low growth rates but within a limited Si: C adatom ratio. A combination of transmission electron microscopy (TEM) and atomic force microscopy (AFM) has been used to examine the different films, and the results of these investigations are described.

True Atomic Level Imaging of Shaped Nanoparticles Composed of Bismuth, Antimony and Tellurium using Scanning Transmission Electron Microscopy.

2011 ◽  
Vol 1349 ◽  
Author(s):  
Derrick Mott ◽  
Nguyen T. Mai ◽  
Teruyoshi Sakata ◽  
Mikio Koyano ◽  
Koichi Higashimine ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Structure ◽  
Scanning Transmission Electron Microscopy ◽  
Level Structure ◽  
Atomic Level ◽  
Transmission Electron ◽  
Bismuth Antimony ◽  
Scanning Transmission ◽  
The Relationship

ABSTRACTNanotechnology is an area of research that is highly intriguing because of the novel properties often observed for materials whose sizes are reduced to the nanoscale. However, one of the biggest challenges is understanding the underlying principles that dictate the particles resulting properties. The atomic level structure for nanoparticles is suspected to vary from that for the corresponding bulk materials, however, direct observation of this phenomenon has proven difficult. Until recently only indirect information on the atomic level structure of such materials could be obtained with techniques such as XRD, HR-TEM, XPS, etc… However, recent advances in Transmission Electron Microscopy techniques now allow true atomic scale resolution, leading to definitive confirmation of the atomic structure. Namely, Scanning Transmission Electron Microscopy coupled with a High-angle Annular Dark Field detector (STEM-HAADF) has been demonstrated to be capable of achieving a nominal resolution of 0.8 nm (the JEOL JEM-ARM200F instrument). The ability is highly exciting because it will lead to an enhanced understanding of the relationship between atomic structure of nanoparticles and the resulting novel properties. In our own study, we focus on the analysis of the atomic level structure for nanoparticles composed of bismuth, antimony and tellurium for thermoelectric materials. This area has recently received much interest because of the realization that nanotechnology can be employed to greatly enhance the efficiency (dimensionless figure of merit ZT) of this class of materials. One of the most intriguing parameters leading to the enhanced TE activity is the relationship between composition and structure that exists within individual nanoparticles. We report our results on a study of the atomic level structure for both nanowires and nanodiscs composed of bismuth, antimony and tellurium. It was found that the nanoparticles have a complex structure that cannot be elucidated by conventional techniques such as XRD or HR-TEM. In addition, by employing Energy Dispersive Spectroscopy (EDS), a greater understanding of the composition-structure dependence was gained. The results are primarily discussed in terms of the atomic level resolution images obtained with the STEM-HAADF technique.

Tem Studies of GaAs/AlGaAs Heterostructures Grown on Patterned Substrates

1987 ◽  
Vol 102 ◽  
Author(s):  
D. M. Hwang ◽  
E. Kapon ◽  
M. C. Tamargo ◽  
J. P. Harbison ◽  
R. Bhat ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Chemical Etching ◽  
Molecular Beam ◽  
Patterned Substrates ◽  
Lateral Direction ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Device Applications ◽  
Substrate Surfaces

ABSTRACTEpitaxical growth rates depend strongly on the crystalline orientations of substrate surfaces. Multilayer growth on pre-patterned substrates with various crystal facets exposed results in a large variation of layer thicknesses in the lateral direction. This lateral definition can be used in device applications. Alternating layers of GaAs and AIGaAs were grown by molecular beam epitaxy on (100) GaAs substrates patterned with grooves and ridges along the [01T] and [011] directions by chemical etching. The results were analyzed with transmission electron microscopy using vertical cross-section techniques. Examples of using this method to fabricate ridges with tips of atomic sharpness and quantum-well lasers are presented.

Molecular Beam Epitaxial Growth of Cdl-xznxTe Matched to HgCdTe Alloys

1986 ◽  
Vol 90 ◽  
Author(s):  
N. Magnea ◽  
F. Dal'bo ◽  
J. L. Pautrat ◽  
A. Million ◽  
L. Di Cioccio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Bulk Material ◽  
Strained Layers ◽  
Molecular Beam Epitaxial ◽  
Transmission Electron ◽  
Molecular Beam Epitaxial Growth ◽  
Thick Layers

ABSTRACTCD1−xZnxTe alloys of various composition have been grown by the Molecular Beam Epitaxy Technique and characterized by Transmission Electron Microscopy. C(V) measurements and photoluminescence spectroscopy techniques. The quality of the thick layers is comparable to that of bulk material. Thin strained layers have also been grown whose interfaces are structurally good. The recombination within a CdTe well confined between Cd1−xZnxTe barriers is dominated by intrinsic processes.

Defects in Mbe-Grown GaAs/ScxEr1–xAs/GaAs Layers

1990 ◽  
Vol 198 ◽  
Author(s):  
Jane G. Zhu ◽  
Chris J. Palmstrdøm ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam Epitaxy ◽  
Growth Stage ◽  
Molecular Beam ◽  
Gaas Layer ◽  
Stacking Fault ◽  
Initial Growth ◽  
Gaas Substrates ◽  
Transmission Electron

ABSTRACTThe microstructure and the structure of defects in GaAs/ScxEr1–xAs/GaAs (x=0 and 0.3) heterostructures grown on (100) GaAs substrates by molecular beam epitaxy have been characterized using transmission electron microscopy. The top GaAs layer forms islands on ScxEr1–xAs at the initial growth stage, and the area covered by GaAs varies with the growth temperature. In addition to regions of epitactic (100) GaAs, regions of {122}- and (111)-oriented GaAs are observed on (100)-oriented ScxEr1–xAs. A high density of stacking-fault pyramids is found in epilayers of GaAs grown on a thin epilayer of ErAs, where the ErAs layers are only one or two monolayers thick. The apex of each stacking-fault pyramid is located at the ScxEr1–xAs/GaAs interface.

Molecular Beam Epitaxial Growth of Gaas on Silicon with Buried Implanted Oxides

1987 ◽  
Vol 107 ◽  
Author(s):  
K. Das ◽  
T.P. Humphreys ◽  
J.B. Posthill ◽  
N. Parikh ◽  
J. Tarn ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Beam ◽  
Antiphase Domain ◽  
Molecular Beam Epitaxial ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
First Results ◽  
Direct Growth ◽  
Molecular Beam Epitaxial Growth ◽  
Microscopy Techniques

AbstractWe report the first results of direct growth of GaAs by molecular beam epitaxy on nominally (100) oriented silicon with buried implanted oxides. Rutherford backscattering and transmission electron microscopy techniques have been used to characterize these layers. The formation of hillocks and a uniform layer of GaAs in the intervening regions between hillocks have been observed. Microtwins, dislocations and antiphase domain boundaries are the predominant defects observed in these layers.

MBE Growth of GaAs on Porous Silicon

1987 ◽  
Vol 91 ◽  
Author(s):  
T. L. Lin ◽  
L. Sadwick ◽  
K. L. Wang ◽  
S. S. Rhee ◽  
Y. C Kao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Porous Silicon ◽  
Surface Morphology ◽  
Molecular Beam ◽  
Stacking Faults ◽  
Rutherford Backscattering ◽  
Mbe Growth ◽  
Transmission Electron ◽  
Minimum Yield

ABSTRACTGaAs layers have been grown on porous silicon (PS) substrates by molecular beam epitaxyNo surface morphology deterioration was observed onGaAs-on-PS layers in spite of the roughness of PS. A 10% Rutherford backscattering spectroscopy (RBS) channeling minimum yield for GaAs-on-PS layers as compared to 16% for GaAs-on-Si layers grown under the same condition indicates a possible improvement of crystallinity when GaAs is grown on PS. Transmission electron microscopy (TEM) reveals that the dominant defects in the GaAs-on-PS layers are microtwins and stacking faults, which originate from the GaAs/PS interface. GaAs is found to penetrate into the PS layers.

Molecular Beam Epitaxial Growth and Characterization of GaAs on Sapphire and Silicon-on-Sapphire Substrates

1988 ◽  
Vol 144 ◽  
Author(s):  
T. P. Humphreys ◽  
C. J. Miner ◽  
N. R. Parikh ◽  
K. Das ◽  
M. K. Summerville ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Beam ◽  
Optical Analysis ◽  
Molecular Beam Epitaxial ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Current Voltage ◽  
Semiconductor Contacts ◽  
Molecular Beam Epitaxial Growth

ABSTRACTEpitaxial GaAs layers have been grown by molecular beam epitaxy on (1012) sapphire and silicon-on-sapphire substrates. The grown layers were characterized by optical and transmission electron microscopy; Rutherford backscattering/channeling of 2.1 MeV He+ ions; Raman spectroscopy; Hall mobility measurements; photoluminescence spectroscopy and current-voltage measurements from metal-semiconductor contacts. The extensive microstructural, electrical and optical analysis of the GaAs layers indicates that the films deposited on silicon-on-sapphire are superior to those grown directly on (1012) sapphire substrates.

Defect Structures in Heteroepitaxial InAs/GaAs and GaAs/InAs Grown by Atomic Layer Molecular Beam Epitaxy

1992 ◽  
Vol 262 ◽  
Author(s):  
S. I. Molina ◽  
G. Aragon ◽  
R. Garcia
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Atomic Layer ◽  
Defect Structures ◽  
Planar Defects ◽  
Transmission Electron

ABSTRACTA Transmission Electron Microscopy (TEM) study on ALMBE grown InAs/GaAs (001) is presented. The density and the types of defects contained in InAs and GaAs layers are clearly different. A relation between the planar defects in these layers and the compressive and extensive nature of the growth for each layer is found. Atomic Layer Molecular Beam Epitaxy (ALMBE) grown InAs layers possess a better quality of defects than other InAs layers grown on GaAs (001) by conventional MBE. Several ways of nucleation are presented as possible for explaining the existence of the different defects found in the studied heterostructure.

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