Antiphase Defect Reduction Mechanism in Mbe Grown Gaas on Si

1989 ◽  
Vol 148 ◽  
Author(s):  
Takashi Shiraishi ◽  
Haruhiko Ajisawa ◽  
Shin Yokoyama ◽  
Mitsuo Kawabe
Keyword(s):  
Electron Microscope ◽  
Antiphase Boundary ◽  
High Energy ◽  
The Self ◽  
Polished Surface ◽  
Reduction Mechanism ◽  
High Energy Electron ◽  
Etch Pits ◽  
Defect Reduction ◽  
Scanning Electron

ABSTRACTIt is shown that antiphase boundary (APB) is annihilated during the growth, by monitoring the surface with reflection high energy electron diffraction (RHEED). The RHEED observation indicates that double domain GaAs changes to single domain within a thickness of 100 nm, while the transition region is estimated to exist within 200 nm from GaAs-Si interface by scanning electron microscope (SEM) observation of etch pits on vicinally polished surface. The self-annihilation mechanism of APB is discussed from these results.

MICRO-FOUR-POINT PROBES IN A UHV SCANNING ELECTRON MICROSCOPE FOR IN-SITU SURFACE-CONDUCTIVITY MEASUREMENTS

2000 ◽  
Vol 07 (05n06) ◽  
pp. 533-537 ◽  
Author(s):  
ICHIRO SHIRAKI ◽  
TADAAKI NAGAO ◽  
SHUJI HASEGAWA ◽  
CHRISTIAN L. PETERSEN ◽  
PETER BØGGILD ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Defects ◽  
High Energy ◽  
Surface Conductivity ◽  
Conductivity Measurements ◽  
Surface Domains ◽  
Unambiguous Detection ◽  
Scanning Electron

For in-situ measurements of surface conductivity in ultrahigh vacuum (UHV), we have installed micro-four-point probes (probe spacings down to 4 μm) in a UHV scanning electron microscope (SEM) combined with scanning reflection–high-energy electron diffraction (RHEED). With the aid of piezoactuators for precise positioning of the probes, local conductivity of selected surface domains of well-defined superstructures could be measured during SEM and RHEED observations. It was found that the surface sensitivity of the conductivity measurements was enhanced by reducing the probe spacing, enabling the unambiguous detection of surface-state conductivity and the influence of surface defects on the electrical conduction.

Synthesis of Al5083 Alloy by High Energy Ball Mill and Densification through Equal Channel Angular Pressing (ECAP)

2019 ◽  
Vol 969 ◽  
pp. 68-72
Author(s):  
K. Chandra Sekhar ◽  
Balasubramanian Ravisankar ◽  
S. Kumaran
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ball Mill ◽  
High Energy ◽  
Mechanically Alloyed ◽  
Channel Angle ◽  
Angular Pressing ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Scanning Electron

An attempt was made to synthesis Al-5083alloy through high energy ball milling and densification through ECAP. The elemental powders consisting of Al5083 was milled for 5, 10 and 15 hrs using Retsch high energy ball mill (PM400). The physical and structural properties of mechanically alloyed particulates were characterised by diffraction methods and electron microscopy. The 15hrs nanocrystalline structured particulates of Al5083 alloy shows crystallite size of 15nm. Scanning Electron Microscope (SEM) reveals the morphology of alloy which is irregular shaped. The size of alloyed particulates also measured using SEM and found to be 7μm for 15hrs of milling. The 15hr milled alloy particulates were densified by ECAP through 90o die channel angle. Maximum densification of 92% and highest hardness of 63HRB was achieved for sample consolidated with route-A for two passes along with sintering.

The Role of Adsorbed Water Molecules in Bulk Restructuring of Amorphous Tungsten Trioxide Films

1995 ◽  
Vol 417 ◽  
Author(s):  
I. V. Shiyanovskaya
Keyword(s):  
Tungsten Trioxide ◽  
Aqueous Electrolyte ◽  
Adsorbed Water ◽  
High Energy ◽  
Water Molecules ◽  
High Energy Electron ◽  
Film Stability ◽  
Influence Of Water ◽  
Scanning Electron

AbstractThe influence of water molecules adsorbed at the surface of electrochromic WO3 films on film stability in aqueous electrolyte has been studied by scanning electron microscopy and high energy electron diffraction.

Self-Propagating High-Temperature Synthesis of Fe-W(B, C) Based Composite

2013 ◽  
Vol 748 ◽  
pp. 46-50 ◽  
Author(s):  
Saowanee Singsarothai ◽  
Sutham Niyomwas
Keyword(s):  
Electron Microscope ◽  
High Temperature ◽  
Scanning Electron Microscope ◽  
The Self ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
X Ray ◽  
High Temperature Synthesis ◽  
Flame Ignition ◽  
Scanning Electron

Fe-W based composite have successfully been prepared using natural resource. The ferberite (Fe (Mn, Sn)WO4) tailings mixed with aluminum, carbon and boron oxide powder were used as reactants. The reactants were pressed and followed by oxy-acetylene flame ignition. The products from the self-propagating high-temperature synthesis (SHS) reaction were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) couple with dispersive X-ray (EDS).

Characterization Techniques For Laser-Annealed Polysilicon on Insulating Layers

1980 ◽  
Vol 1 ◽  
Author(s):  
J. T. Schott ◽  
J. J. Comer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Energy ◽  
High Energy Electron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Characterization Techniques ◽  
Cw Laser ◽  
Transmission Electron ◽  
Scanning Electron

ABSTRACTVarious characterization techniques are applied to pulsed and cw laser-annealed polysilicon layers deposited on oxide layers. The results are used to compare these techniques as to the type and completeness of information provided, as well as sample preparation requirements and general ease or difficulty of measurement. The techniques employed include scanning electron microscopy (SEM), electron channeling micrographs and selected area channeling patterns (SACP), reflection (high energy) electron diffraction (RHEED), transmission electron microscopy (TEM) and selected area diffraction (SAD), x-ray diffraction, optical techniques and etching techniques.

Surface ornamentation of the echinoid test and its ecologic significance

Paleobiology ◽  
1976 ◽  
Vol 2 (2) ◽  
pp. 122-130 ◽  
Author(s):  
Susan C. Oldfield
Keyword(s):  
Growth Rate ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Outer Surface ◽  
High Growth ◽  
High Energy ◽  
Low Energy ◽  
Plate Surface ◽  
Surface Ornamentation ◽  
Scanning Electron

A scanning electron microscope survey of the regular echinoid test reveals that the outer surface of its component coronal plates may be sculptured with a fine-relief ornament that is species-characteristic for those species presently surveyed. Structural resemblances in surface ornamentation are more marked in species living in similar habitats than in those species that are apparently phyletically related. Plate ornament is related to skeletal magnesium levels. It is tentatively suggested that low growth rate echinoids that inhabit “low-energy” environments (and exhibit low total skeletal magnesium levels) and “high-energy” habitat-exploiting species with high growth rates (and relatively high skeletal magnesium levels) may have differential patterns of plate growth that can be distinguished by the degree of ornamentation of the plate surface.

Modification of a TEM for ultra-high-vacuum reflection-EM (UHV-REM) applications

1995 ◽  
Vol 53 ◽  
pp. 582-583
Author(s):  
Tung Hsu ◽  
Min-Yi Shih ◽  
A. V. Latyshev
Keyword(s):  
Electron Microscope ◽  
High Vacuum ◽  
High Energy ◽  
Ultra High Vacuum ◽  
Objective Lens ◽  
Pole Piece ◽  
High Energy Electron ◽  
Normal Position ◽  
Crystal Surfaces ◽  
Specimen Holder

A JEOL JEM-100C electron microscope was modified by adding a cryogenic UHV specimen holder for studying clean crystal surfaces with the reflection high energy electron diffraction (RHEED) and REM techniques. The Si(111) (l×l) and (7×7) phase transitions have been successfully observed (Fig. 1). Further modification is in progress for better resolution and other functions. Fig. 2.a shows the unmodified specimen holder and the objective lens of the microscope. The cryogenic holder based on the Novosibirsk design is shown in Fig. 2.b. Liquid nitrogen is continuously pumped through the shell of the holder for achieving UHV inside. The tilt/rotation controls and the current for heating of the specimen are fed through the holder. In this modification, the specimen was not placed at the normal position of the lens and therefore is not at the best position for imaging and diffraction.A new holder is shown in Fig. 2.c. This holder is inserted into the pole piece to place the specimen at the normal position.

Preparation of WSi2 by RTA Annealing of CVD-W thin Films

1995 ◽  
Vol 402 ◽  
Author(s):  
K. A. Gesheva ◽  
G. I. Stoyanov ◽  
D. S. Gogova ◽  
G. D. Beshkov
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
Atmospheric Pressure ◽  
High Energy ◽  
Argon Atmosphere ◽  
High Energy Electron ◽  
Different Gases ◽  
Scanning Electron

AbstractWsi2 films were prepared by rapid thermal annealing (RTA) in the temperature range of 800 -1400 °C for time durations of 15 sec -3 minutes. In some of the treatment experiments different gases were involved and a conclusion is made about the role of hydrogen favoring Wsi crystal phase growing at 800 °C. W films with thichnesses in the range 200 Å - 1000 Å were deposited on monocrystalline Si by pyrolitical decomposition of W(CO)6 in CVD reactor at atmospheric pressure and argon atmosphere. Reflection High Energy Electron Diffraction (RHEED) and Scanning Electron Microscopy (SEM) technics were used for structural characterization and FPP-100 device for resistance measurements. Results show that by solid state reaction applied at different RTA processes WSi2 phase could be formed.Resistivities as low as 2-3 mΩ.cm are obtained for 800 -1000 °C.

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