Characterization and Growth Mechanism of B12As2 Epitaxial Layers Grown on (1-100) 15R-SiC

2008 ◽  
Vol 1069 ◽  
Author(s):  
Hui Chen ◽  
Guan Wang ◽  
Michael Dudley ◽  
Zhou Xu ◽  
James. H. Edgar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Growth Mechanism ◽  
Heteroepitaxial Growth ◽  
High Quality ◽  
X Ray ◽  
Transmission Electron ◽  
Substrate Choice

ABSTRACTA systematic study is presented of the heteroepitaxial growth of B12As2 on m-plane 15R-SiC. In contrast to previous studies of B12As2 on other substrates, including (100) Si, (110) Si, (111) Si and (0001) 6H-SiC, single crystalline and untwinned B12As2 was achieved on m-plane 15R-SiC. Observations of IBA on m-plane (1100)15R-SiC by synchrotron white beam x-ray topography (SWBXT) and high resolution transmission electron microscopy (HRTEM) confirm the good quality of the films on the 15R-SiC substrates. The growth mechanism of IBA on m-plane 15R-SiC is discussed. This work demonstrates that m-plane 15R-SiC is potentially a good substrate choice to grow high quality B12As2 epilayers.

scholarly journals Mechanism for Improved Quality B12As2 Epitaxial Films on (0001) 4H-SiC Substrates by Tilting toward [1-100] Direction

2010 ◽  
Vol 1246 ◽  
Author(s):  
Yu Zhang ◽  
Hui Chen ◽  
Michael Dudley ◽  
Yi Zhang ◽  
James Edgar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Substrate Surface ◽  
Epitaxial Films ◽  
High Quality ◽  
X Ray ◽  
Transmission Electron ◽  
Device Applications ◽  
Substrate Choice ◽  
Single Orientation

AbstractIn this work, 4H-SiC substrates intentionally misoriented from the (0001) plane toward [1-100] direction are shown to eliminate rotational twinning in icosahedral boron arsenide (B12As2, abbreviated here as IBA) epitaxial films. Previous studies of IBA on other substrates, including (100), (110), (111) Si and (0001) 6H-SiC, produced polycrystalline and twinned epilayers. Comparisons of IBA on on-axis and off-axis c-plane 4H-SiC by synchrotron white beam x-ray topography (SWBXT), and high resolution transmission electron microscopy (HRTEM) confirm the single crystalline and much higher quality of the films on the latter substrates. Furthermore, no intermediate layer between the epilayer and substrate was observed for IBA on off-axis 4H-SiC. Steps formed on the off-axis 4H-SiC substrate surface before deposition cause the film to adopt a single orientation, a process that is not seen with substrates with either no misorientation, or those tilted toward the [11-20] direction. This work demonstrates that c-plane 4H-SiC with 7° offcut toward (1-100) is potentially a good substrate choice for the growth of high-quality, untwinned B12As2 epilayers for future device applications.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

scholarly journals Synthesize and Characterization of Hollow Boron-Nitride Nanocages

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
W. S. Zhang ◽  
J. G. Zheng ◽  
W. F. Li ◽  
D. Y. Geng ◽  
Z. D. Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Boron Nitride ◽  
Growth Mechanism ◽  
Spherical Shape ◽  
Amorphous Boron ◽  
Transmission Electron ◽  
Ammonia Atmosphere

The boron-nitride (BN) nanocages are synthesized by nitrogenation of amorphous boron nanoparticles at 1073 K under nitrogen and ammonia atmosphere. The BN nanocages exhibit a well-crystallized feature with nearly pentagonal or spherical shape, depending on their size. High-resolution transmission electron microscopy studies reveal that they are hollow nanocages. The growth mechanism of the BN nanocages is proposed.

scholarly journals Microstructure and Stability Comparison of Nanometer Period W/C, Wc/C, and Ru/C Multilayer Structures

1990 ◽  
Vol 187 ◽  
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Layered Structures ◽  
Multilayer Structures ◽  
X Ray ◽  
Transmission Electron

AbstractMultilayer structures of W/C, WC/C, and Ru/C, of various periods were prepared and studied by high-resolution transmission electron microscopy. Comparison of the phases in the layered structures is made for as-prepared and annealed samples. Both as-prepared and annealed WC/C multilayers are predominantly amorphous, while the phases in the W/C depend on the periods. The 2 nm period W/C multilayer remains amorphous after annealing, and the longer periods recrystallize to form W2C. The layered microstructures of W/C and WC/C are stable on annealing at all periods, while the amorphous Ru-rich layers in the 2 nm period Ru/C multilayer agglomerate upon annealing to form elemental hexagonal Ru crystallites. Larger period Ru/C multilayers show stable layered structures, and indicate hexagonal Ru in the Ru-rich layers. X-ray measurements show that the multilayer periods expand on annealing for all metal-carbon multilayers studied.

HRTEM Investigation of Precipitates in Al-Zn-In-Mg-Ti-Ce Anode Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 1036-1039
Author(s):  
Jing Ling Ma ◽  
Jiu Ba Wen ◽  
Yan Fu Yan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Hexagonal Structure ◽  
Orientation Relation ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Scanning Electron

The precipitates of Al-5Zn-0.02In-1Mg-0.05Ti-0.5Ce (wt %) anode alloy were studied by scanning electron microscopy, X-ray microanalysis, high resolution transmission electron microscopy and selected area electron diffraction analyses in the present work. The results show that the alloy mainly contains hexagonal structure MgZn2 and tetragonal structure Al2CeZn2 precipitates. From high resolution transmission electron microscopy and selected area electron diffraction, aluminium, Al2CeZn2 and MgZn2 phases have [0 1 -1]Al|| [1 -10]Al2CeZn2|| [-1 1 0 1]MgZn2orientation relation, and Al2CeZn2 and MgZn2 phases have the [0 2 -1]Al2CeZn2|| [0 1 -10]MgZn2orientation relation.

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