High‐resolution electron microscopy of growth interruption effect on AlAs/GaAs interfacial structure during molecular beam epitaxy

1992 ◽  
Vol 60 (11) ◽  
pp. 1360-1362 ◽  
Author(s):  
Nobuyuki Ikarashi ◽  
Masaaki Tanaka ◽  
Hiroyuki Sakaki ◽  
Koichi Ishida
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Growth Interruption ◽  
Resolution Electron

scholarly journals The Structure of Al/GaAs Interfaces

1986 ◽  
Vol 77 ◽  
Author(s):  
Zuzanna Liliental-Weber ◽  
C. Nelson ◽  
R. Gronsky ◽  
J. Washburn ◽  
R. Ludeke
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Substrate Temperature ◽  
Epitaxial Growth ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron ◽  
Molecular Beam Epitaxy Chamber

ABSTRACTThe structure of Al/GaAs interfaces was investigated by high resolution electron microscopy. The Al layers Were deposited in a molecular beam epitaxy chamber with a vacuum base pressure of <1×10∼8 Pa. The GaAs substrate temperature varied during Al deposition from -30°C to 400°C. Deposition of Al on cold substrates £25°C resulted in epitaxial growth of (001) Al on (001) GaAs. Droplets of Ga were observed in samples with the substrate temperature at -30°C (1×2) and 0°C (c(2×8)). Postannealing of the last sample caused formation of the AlGaAs phase. Deposition of Al on hot substrates (150°C and 400°C) resulted in the formation of the AlGaAs phase, which separated (110) oriented Al from (001)GaAs.

High‐resolution electron microscopy study of (Ca,Sr)F2/GaAs grown by molecular‐beam epitaxy

1987 ◽  
Vol 61 (6) ◽  
pp. 2410-2412 ◽  
Author(s):  
Hélène Héral ◽  
Louis Bernard ◽  
André Rocher ◽  
Chantal Fontaine ◽  
Antonio Munoz‐Yague
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Resolution Electron

HRTEM simulation of interfacial structure in amorphous multilayers

1989 ◽  
Vol 47 ◽  
pp. 466-467
Author(s):  
Margaret L. Sattler ◽  
Michael A. O'Keefe
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Cross Section ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Multilayer Sample ◽  
Resolution Electron ◽  
Multilayered Materials ◽  
Simulated Images

Multilayered materials have been fabricated with such high perfection that individual layers having two atoms deep are possible. Characterization of the interfaces between these multilayers is achieved by high resolution electron microscopy and Figure 1a shows the cross-section of one type of multilayer. The production of such an image with atomically smooth interfaces depends upon certain factors which are not always reliable. For example, diffusion at the interface may produce complex interlayers which are important to the properties of the multilayers but which are difficult to observe. Similarly, anomalous conditions of imaging or of fabrication may occur which produce images having similar traits as the diffusion case above, e.g., imaging on a tilted/bent multilayer sample (Figure 1b) or deposition upon an unaligned substrate (Figure 1c). It is the purpose of this study to simulate the image of the perfect multilayer interface and to compare with simulated images having these anomalies.

Atomic Structure of Interfaces: Link of Atomistic Calculations with High Resolution Electron Microscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 762-763
Author(s):  
V. Vitek
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Computer Modeling ◽  
Atomic Structure ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Embedded Atom ◽  
Resolution Electron ◽  
Atomic Interactions ◽  
Atomistic Calculations

Since interfaces and grain boundaries affect critically many properties of materials, their atomic structure has been investigated very extensively using computer modeling. Most of these calculations have been made using semi-empirical central-force descriptions of atomic interactions, recently primarily the embedded-atom type many-body potentials. Owing to the approximate nature of such schemes, a connection with experimental observations that can validate the calculations is essential. The high resolution electron microscopy (HREM) is such experimental technique and it has, indeed, been frequently combined with calculations of interfacial structure and chemistry. In fact such a link is not only important for verification of the results of computer modeling but also crucial for meaningful interpretation of HREM observations. Hence, coupling the atomistic modeling with HREM is a synergistic procedure. It not only leads to better understanding of interfacial structures but may contribute significantly to the validation and assessment of limits of the schemes used for the description of atomic interactions.

A HREM study of V/Al2O3 interface

1992 ◽  
Vol 50 (1) ◽  
pp. 146-147
Author(s):  
Y. Ikuhara ◽  
P. Pirouz ◽  
A. H. Heuer ◽  
S. Yadavalli ◽  
C. P. Flynn
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
High Resolution ◽  
Substrate Temperature ◽  
Molecular Beam ◽  
High Resolution Electron Microscopy ◽  
Interface Structure ◽  
Cross Sectional ◽  
Plan View ◽  
Resolution Electron

The interface structure between vanadium and the R-plane of sapphire (α-Al2O3) was studied by conventional and cross-sectional high resolution electron microscopy (HREM) to clarify the atomic structure of the interface.A 57 nm thick vanadium film was deposited on the (1102) (R) plane of sapphire by molecular beam epitaxy (MBE) at a substrate temperature of 920 K in a vacuum of 10-10torr. The HREM observations of the interface were done from three directions: two cross-sectional views (parallel to [0221]Al2O3 and [1120]Al2O3) and a plan view (parallel to [2201]Al2O3) by a top-entry JEOL 4000EX electron microscope (400 kV).

Transmission Electron Microscopy studies of the structure of martensitic interfaces in Cu-Zn: HRTEM

1990 ◽  
Vol 48 (4) ◽  
pp. 314-315
Author(s):  
F.-R. Chen ◽  
G. B. Olson
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Habit Plane ◽  
Parent Phase ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Second Phase ◽  
Invariant Line ◽  
Lattice Plane ◽  
Resolution Electron

The crystallography and interfacial structure of martensite in Cu-38.6%Zn has been studied by conventional TEM and reported in these proceedings. The parent phase is bcc and the martensite phase has a 9R close-packed structure with the stacking order “ABC/BCA/CAB/A” normal to the c axis. Here, the bcc-9R interfaces are studied by using high resolution electron microscopy. The coherency dislocation/step structure of enclosed second phase particles has been treated by Olson and Cohen. The most significant coherency dislocation/step in an interface is formed by the intersection of interface and the most close-packed lattice plane which is nearly parallel to the interface. The average habit plane of martensite in Cu-38.6%Zn determined from experiment and CRAB crystallographic theory is very close to (4 21 22)b which is 7.6° away from the most close-packed lattice plane (011)b. Therefore, the best crystallographic direction for high-resolution electron microscopy studies is [01]b where the habit plane and the (011)b are all edge-on. Unfortunately, in this beam direction there is only one set of lattice fringes from both parent and martensite phases which can be resolved and they provide little information about interfacial structure. As shown in Figure 1 the high resolution images are therefore taken along the [11]b lattice invariant line (anti-coherency dislocation line) direction where the interfacial boundary and the internal stacking faults of the martensite are near edge-on. Figure 1 (a) and (b) are in the same area but taken with different defocus. These images were taken using the Berkeley ARM operated at 800 kv.

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