Microstructural Characterization of Low Temperature GaAs(111)B MBE Growth by AFM and Tem

1992 ◽  
Vol 280 ◽  
Author(s):  
M. P. de Boer ◽  
J. E. Angelo ◽  
A. M. Dabiran ◽  
P. I. Cohen ◽  
W. W. Gerberich
Keyword(s):  
Low Temperature ◽  
Microstructural Characterization ◽  
Cross Sectional ◽  
Plan View ◽  
Mbe Growth ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Low Temperature Gaas

ABSTRACTAtomic Force Microscopy (AFM) images are correlated with Transmission Electron Microscopy (TEM) plan-view images in a structure consisting of <111> oriented GaAs layers grown by molecular beam epitaxy (MBE) at 500°C. We present results on the applicability of AFM, which requires short sample preparation and imaging time relative to TEM, in obtaining information on twin density and growth pits of these low temperature samples. Also, we discuss the behavior of twin boundaries by comparing plan-views and cross sectional TEM images.

scholarly journals Influence of hematite nanorods on the mechanical properties of epoxy resin

2017 ◽  
Vol 82 (4) ◽  
pp. 437-447 ◽  
Author(s):  
Gordana Bogdanovic ◽  
Tijana Kovac ◽  
Enis Dzunuzovic ◽  
Milena Spírková ◽  
Phillip Ahrenkiel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Microstructural Characterization ◽  
Uniform Size ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Uniform Size Distribution ◽  
Tensile Toughness

The mechanical properties of nanocomposites obtained by incorporation of fairly uniform hematite nanorods (?-Fe2O3 NRs) into epoxy resin were studied as a function of the content of the inorganic phase. A thorough microstructural characterization of the ?-Fe2O3 NRs and the nanocomposites was performed using transmission electron microscopy (TEM) and atomic force microscopy (AFM). The TEM measurements revealed rod-like morphology of the nanofiller with a uniform size distribution (8.5 nm?170 nm, diameter?length). High-magnification TEM and AFM measurements indicated agglomeration of ?-Fe2O3 NRs embedded in the epoxy resin. Stress at break, strain at break, elastic modulus and tensile toughness of the nanocomposites were compared with the data obtained for pure epoxy resin. Significant influence of nanofiller on the mechanical properties of epoxy resin, as well as on the glass transition temperature, could be noticed for samples with low contents of the inorganic phase (up to 1 wt. %).

Microstructural Characterization of 3C-SiC Thin Films Grown by Flash Lamp Induced Liquid Phase Epitaxy

2005 ◽  
Vol 483-485 ◽  
pp. 295-298 ◽  
Author(s):  
Gabriel Ferro ◽  
D. Panknin ◽  
Efstathios K. Polychroniadis ◽  
Yves Monteil ◽  
Wolfgang Skorupa ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Liquid Phase Epitaxy ◽  
Structural Characteristics ◽  
Microstructural Characterization ◽  
Si Substrate ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Thin 3C-SiC films epitaxially grown on Si-substrate are substantially improved by the FLASIC process, which involves irradiation with flash lamps with pulse duration of 20ms. The disadvantages of the standard FLASIC process are the undulations introduced in the SiC film due to melting of the Si-substrate and the Si mass transport near the SiC/Si interface during the flash. An improved structure was realised in order to minimize the undulations of the SiC, improving also the quality of the film. This structure involves the deposition of a silicon overlayer (SOL) on the initial SiC layer, followed by an additional SiC capping layer acting as a source for SiC transfer by liquid phase epitaxy to the lower SiC layer. Significant mass SiC transport from the upper to the lower SiC layer through the SOL occurs during the flash. The new structure is characterized as inverse - FLASiC. The structural characteristics of the new structure were studied by transmission electron microscopy and atomic force microscopy.

Nucleation and Growth of {113} Defects and {111} Dislocation Loops Insilicon-Implanted Selicon

1997 ◽  
Vol 469 ◽  
Author(s):  
G. Z. Pan ◽  
K. N. Tu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microstructural Characterization ◽  
Nucleation And Growth ◽  
Growth Behavior ◽  
Dislocation Loops ◽  
Cross Sectional ◽  
Plan View ◽  
Transmission Electron

ABSTRACTPlan-view and cross-sectional transmission electron microscopy have been used to study the microstructural characterization of the nucleation and growth behavior of {113} rodlike defects, as well as their correlation with {111} dislocation loops in silicon amorphized with 50 keV, 36×1014 Si/cm2, 8.0 mAand annealed by rapid thermal anneals at temperatures from 500 °C to 1100 °C for various times. We found that the nucleations of the {113} rodlike defects and {111} dislocation loops are two separate processes. At the beginning of anneals, excess interstitials accumulate and form circular interstitial clusters at the preamorphous/crystalline interface at as low as 600 °C for 1 s. Then these interstitial clusters grow along the <110> direction to form {113} rodlike defects. Later, while the {113} defects have begun to grow and/or dissolve into matrix, the {111} faulted Frank dislocation loops start to form. We also found that the initial interstitial clusters prefer to grow along the <110>directions inclined to the implantation surface.

Structure of Carrot Defects in 4H-SiC Epilayers

2006 ◽  
Vol 527-529 ◽  
pp. 327-332 ◽  
Author(s):  
X. Zhang ◽  
Seo Young Ha ◽  
M. Benamara ◽  
Marek Skowronski ◽  
Joseph J. Sumakeris ◽  
...  
Keyword(s):  
Basal Plane ◽  
Cross Sectional ◽  
Plan View ◽  
X Ray ◽  
Force Microscopy ◽  
Carrier Recombination ◽  
Atomic Force ◽  
Transmission Electron ◽  
Homoepitaxial Layers ◽  
Koh Etching

Structure of the “carrot” defects in 4H-SiC homoepitaxial layers deposited by CVD has been investigated by plan-view and cross-sectional transmission x-ray topography, cross-sectional transmission electron microscopy, atomic force microscopy, and KOH etching. The carrot defects nucleate at the substrate/epilayer interface at the emergence points of threading screw dislocations propagating from the substrate. The typical defect consists of two stacking faults: one in the prismatic plane with second one in the basal plane. The faults are connected by a stair-rod dislocation with Burgers vector 1/n[10-10] with n>3 at the cross-over. The basal plane fault is of Frank-type. Carrot defects are electrically active as evidenced by contrast in EBIC images indicating enhanced carrier recombination rate. Presence of carrot defects in the p-i-n diodes results in higher pre-breakdown reverse leakage current and approximately 50% lower breakdown voltage compared to the nominal value.

Structural Characterization of Graphene Grown by Thermal Decomposition of Off-Axis 4H-SiC (0001)

2012 ◽  
Vol 711 ◽  
pp. 141-148 ◽  
Author(s):  
Filippo Giannazzo ◽  
Martin Rambach ◽  
Wielfried Lerch ◽  
Corrado Bongiorno ◽  
Salvatore di Franco ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Cross Section ◽  
Structural Characterization ◽  
Plan View ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

We present a nanoscale morphological and structural characterization of few layers of graphene grown by thermal decomposition of off-axis 4H-SiC (0001). A comparison between transmission electron microscopy (TEM) in cross-section and in plan view allows to fully exploit the potentialities of TEM. Such a comparison was used to get information on the number of graphene layers as well as on the rotational order between the layers and with respect to the substrate. Some peculiar structures observed by TEM (wrinkles) could only be systematically measured by atomic force microscopy (AFM). In particular, the density and the height of the wrinkles in the few layers of graphene was investigated.

The Microstructural Characterization of Nanocrystalline CeO2 Ceramics Produced by the Sol-Gel Method

1994 ◽  
Vol 343 ◽  
Author(s):  
F. Czerwinski ◽  
J.A. Szpunar
Keyword(s):  
Sol Gel ◽  
Microstructural Characterization ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Structure Of Coatings ◽  
Heating Up

ABSTRACTCeO2 ceramics were manufactured in the form of surface coatings deposited onto various substrates by sol-gel technology. The size of the CeO2 crystallites, dried at room temperature, was about 5 nm and did not change significantly after heating, up to 680 K. Further increase of the temperature resulted in a rapid growth of crystallites. The process of growth depends also on the film thickness and nature of substrate. The results obtained using thermogravimetric analysis (TGA) and infrared spectroscopy (IR) demonstrated that the thermal decomposition of gel was completed at about 750 K. There was no evident texture in both the as-deposited state and after heat-treatment. X-ray diffraction (XRD), the atomic force microscopy (AFM), and transmission electron microscopy (TEM) were used to characterize the structure of coatings. The examples of application of CeO2 ceramics as coatings for high temperature corrosion protection are presented. The role of size of CeO2 particles in modification of grain boundary transport is discussed.

Defects In 4H Silicon Carbide CVD Epilayers

1996 ◽  
Vol 442 ◽  
Author(s):  
L. Zhou ◽  
P. Pirouz ◽  
J. A. Powell
Keyword(s):  
Formation Mechanism ◽  
Chemical Vapor ◽  
Cross Sectional ◽  
Plan View ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Steps ◽  
Transmission Electron ◽  
Surface Decoration ◽  
Decoration Technique

AbstractThe characteristic defects of 4H-SiC homoepitaxial thin films grown on bulk substrates using chemical vapor deposition (CVD) are described based on transmission electron microscopy (TEM), atomic force microscopy (AFM) and surface decoration studies. Emphasis is placed on understanding the formation mechanism of surface triangular defects. Cross-sectional TEM observations revealed the existence of two variants of 3C-SiC inclusions in 4H epitaxial films. In the plan-view orientation, g4H = 3304 type reflections were found useful for distinguishing the two variants of 3C-SiC platelets that are present in the 4H epilayer. A decoration technique was employed to reveal the relationship between the 3C platelets and surface features, e.g., surface steps. A formation mechanism for surface triangular defects is proposed, which is partially confirmed by the etch pit patterns obtained on the epilayer surfaces after a molten KOH etch.

Temperature Dependent Quasi-Periodic Facetting of AlAs Grown by MBE on (100) GaAs Substrates

1993 ◽  
Vol 312 ◽  
Author(s):  
Richard Mirin ◽  
Mohan Krishnamurthy ◽  
James Ibbetson ◽  
Arthur Gossard ◽  
John English ◽  
...  
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
High Energy Electron ◽  
Temperature Dependent ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Atomic Force ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Facet Formation

AbstractHigh temperature (≥ 650°C) MBE growth of AlAs and AlAs/GaAs superlattices on (100) GaAs is shown to lead to quasi-periodic facetting. We demonstrate that the facetting is only due to the AlAs layers, and growth of GaAs on top of the facets replanarizes the surface. We show that the roughness between the AlAs and GaAs layers increases with increasing number of periods in the superlattice. The roughness increases to form distinct facets, which rapidly grow at the expense of the (100) surface. Within a few periods of the initial facet formation, the (100) surface has disappeared and only the facet planes are visible in cross-sectional transmission electron micrographs. At this point, the reflection high-energy electron diffraction pattern is spotty, and the specular spot is a distinct chevron. We also show that the facetting becomes more pronounced as the substrate temperature is increased from 620°C to 710°C. Atomic force micrographs show that the valleys enclosed by the facets can be several microns long, but they may also be only several nanometers long, depending on the growth conditions.

Structural and Morphological Characterization of Ultrathin Films of an Asymmetric Polydiacetylene

1996 ◽  
Vol 440 ◽  
Author(s):  
H. C. Wang ◽  
D. W. Cheong ◽  
J. Kumar ◽  
C. Sung ◽  
S. K. Tripathy
Keyword(s):  
Second Harmonic ◽  
Morphological Characterization ◽  
Lb Films ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Glass Substrates ◽  
Atomic Force ◽  
Transmission Electron ◽  
Air Water Interface

AbstractA soluble, asymmetrically substituted polydiacetylene, poly(BPOD), has been reported to form stable monolayers at the air-water interface by the Langmuir-Blodgett (LB) technique [2]. Preformed polydiacetylene has been deposited onto hydrophobic substrates as multilayers to form second order nonlinear optical thin films. Second harmonic generation was found to increase with the number of layers. From previous atomic force microscopy (AFM) studies backbone orientation along the dipping direction with an interchain spacing of about 5 A° was indicated [2].The film morphology and preferential molecular orientation of these LB films are further investigated by transmission electron microscopy (TEM). A specifically tailored sample preparation method for the ultrathin LB films was used. Multilayer films were deposited on hydrophobic collodion covered glass substrates for this purpose. Electron diffraction was employed to study the crystalline organization of mono and multilayers of LB films as well as cast films.

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