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.

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.

Elimination of Degenerate Epitaxy in the Growth of High Quality B12As2 Single Crystalline Epitaxial Films

2011 ◽  
Vol 1307 ◽  
Author(s):  
Yu Zhang ◽  
Hui Chen ◽  
Michael Dudley ◽  
Yi Zhang ◽  
J. H. Edgar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Epitaxial Films ◽  
High Quality ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Single Orientation

ABSTRACTElimination of degenerate epitaxy in the growth of icosahedral boron arsenide (B12As2, abbreviated as IBA) was achieved on m-plane 15R-SiC substrates and 4H-SiC substrates intentionally misoriented by 7 degrees from (0001) towards [1-100]. Synchrotron white beam x-ray topography (SWBXT) revealed that only single orientation IBA was present in the epitaxial layers demonstrating the absence of twin variants which dominantly constitute the effects of degenerate epitaxy. Additionally, low asterism in the IBA diffraction spots compared to those grown on other SiC substrates indicates a superior film quality. Cross-sectional high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) both confirmed the absence of twins in the IBA films and their high quality. The ease of nucleation on the ordered step structures present on these unique substrates overrides symmetry considerations that drive degenerate epitaxy and dominates the nucleation process of the IBA.

scholarly journals Epitaxial Growth of Ordered In-Plane Si and Ge Nanowires on Si (001)

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 788
Author(s):  
Jian-Huan Wang ◽  
Ting Wang ◽  
Jian-Jun Zhang
Keyword(s):  
Electron Microscopy ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
Core Shell ◽  
High Quality ◽  
Quantum Devices ◽  
Wafer Scale ◽  
Transmission Electron ◽  
Controllable Growth

Controllable growth of wafer-scale in-plane nanowires (NWs) is a prerequisite for achieving addressable and scalable NW-based quantum devices. Here, by introducing molecular beam epitaxy on patterned Si structures, we demonstrate the wafer-scale epitaxial growth of site-controlled in-plane Si, SiGe, and Ge/Si core/shell NW arrays on Si (001) substrate. The epitaxially grown Si, SiGe, and Ge/Si core/shell NW are highly homogeneous with well-defined facets. Suspended Si NWs with four {111} facets and a side width of about 25 nm are observed. Characterizations including high resolution transmission electron microscopy (HRTEM) confirm the high quality of these epitaxial NWs.

CHARACTERIZATION AND ELECTRICAL PROPERTIES OF ALIGNED CARBON NANOTUBES WITH HIGH ASPECT RATIO

2011 ◽  
Vol 10 (01n02) ◽  
pp. 23-28
Author(s):  
RAVI BHATIA ◽  
V. PRASAD ◽  
M. REGHU
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Multiwall Carbon Nanotubes ◽  
High Quality ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
High Degree

High-quality multiwall carbon nanotubes (MWNTs) were produced by a simple one-step technique. The production of MWNTs was based on thermal decomposition of the mixture of a liquid phase organic compound and ferrocene. High degree of alignment was noticed by scanning electron microscopy. The aspect ratio of as-synthesized MWNTs was quite high (more than 4500). Transmission electron microscopy analysis showed the presence of the catalytic iron nanorods at various lengths of MWNTs. Raman spectroscopy was used to know the quality of MWNTs. The ratio of intensity of the G-peak to the D-peak was very high which revealed high quality of MWNTs. Magnetotransport studies were carried out at low temperature and a negative MR was noticed.

Epitaxial Growth of Aluminum Nitride on Sapphire and Silicon

1994 ◽  
Vol 358 ◽  
Author(s):  
K. Dovidenko ◽  
S. Oktyabrsky ◽  
J. Narayan ◽  
M. Razeghi
Keyword(s):  
Epitaxial Growth ◽  
Substrate Surface ◽  
Wide Band ◽  
X Ray Diffraction ◽  
Wide Band Gap ◽  
High Quality ◽  
Microstructural Characteristics ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron

ABSTRACTThe microstructural characteristics of wide band gap semiconductor, hexagonal A1N thin films on Si(100), (111), and sapphire (0001) and (10ī2) were studied by transmission electron microscopy (TEM) and x-ray diffraction. The films were grown by MOCVD from TMA1 + NH3 + N2 gas mixtures. Different degrees of film crystallinity were observed for films grown on α-A12O3 and Si substrates in different orientations. The epitaxial growth of high quality single crystalline A1N film on (0001) α-Al2O3 was demonstrated with a dislocation density of about 2*10 10cm−2 . The films on Si(111) and Si(100) substrates were textured with the c-axis of A1N being perpendicular to the substrate surface.

Heterointerface quality of InGaP–GaAs superlattices determined by photopumping, x-ray analysis, and transmission electron microscopy

1999 ◽  
Vol 75 (8) ◽  
pp. 1101-1103 ◽  
Author(s):  
Q. Yang ◽  
D. A. Kellogg ◽  
C. Lin ◽  
G. E. Stillman ◽  
N. Holonyak
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
X Ray ◽  
Transmission Electron

Thick PLZT Films Grown by Sol-gel for Optical Device Applications

1998 ◽  
Vol 541 ◽  
Author(s):  
M. Linnik ◽  
O. Wilson ◽  
A. Christou
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Phase Modulator ◽  
X Ray Diffraction ◽  
X Ray ◽  
Device Applications ◽  
Gel Technique ◽  
Scanning Electron

AbstractThe preparation and characterization of thick PLZT films for spatial phase modulator applications are reported. Films were fabricated on LSCO/LAO substrates by a sol-gel technique using multiple heat-treatment parameters. The crystal quality of PLZT 9/65/35 films was investigated by X-ray diffraction and scanning electron microscopy.

Microstructure and growth of joins in melt-textured YBa2Cu3O7−δ

2001 ◽  
Vol 16 (8) ◽  
pp. 2298-2305 ◽  
Author(s):  
A. D. Bradley ◽  
W. Lo ◽  
M. Mironova ◽  
N. H. Babu ◽  
D. A. Cardwell ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Liquid Phase ◽  
Grain Boundary ◽  
Electron Probe ◽  
High Quality ◽  
Strongly Coupled ◽  
External Agent ◽  
Transmission Electron

Joining of melt-textured YBa2Cu3O7-δ (Y123) grains has been achieved without use of an external agent. The technique uses barium-cuprate liquid phase released from platelet boundaries to mediate the growth of Y123 at the interface between two grains. The epitaxial nature and high quality of the growth was determined by optical and transmission electron microscopy. The composition of Ba–Cu–O phases found in some parts of the joins was determined by electron probe microanalysis. A clean low-angle join was found to consist of a grain boundary with dislocation networks and facets. Transport critical current measurements on this type of join revealed strongly coupled behavior. The technique shows promise for the joining of melt-textured material for power engineering applications.

scholarly journals Transmission electron microscopy as a tool for nanocrystal characterization pre- and post-injector

2014 ◽  
Vol 369 (1647) ◽  
pp. 20130322 ◽  
Author(s):  
H. P. Stevenson ◽  
D. P. DePonte ◽  
A. M. Makhov ◽  
James F. Conway ◽  
O. B. Zeldin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Free Electron Laser ◽  
Coherent Light ◽  
Delivery Method ◽  
X Ray ◽  
Transmission Electron ◽  
Linac Coherent Light Source

Recent advancements at the Linac Coherent Light Source X-ray free-electron laser (XFEL) enabling successful serial femtosecond diffraction experiments using nanometre-sized crystals (NCs) have opened up the possibility of X-ray structure determination of proteins that produce only submicrometre crystals such as many membrane proteins. Careful crystal pre-characterization including compatibility testing of the sample delivery method is essential to ensure efficient use of the limited beamtime available at XFEL sources. This work demonstrates the utility of transmission electron microscopy for detecting and evaluating NCs within the carrier solutions of liquid injectors. The diffraction quality of these crystals may be assessed by examining the crystal lattice and by calculating the fast Fourier transform of the image. Injector reservoir solutions, as well as solutions collected post-injection, were evaluated for three types of protein NCs (i) the membrane protein PTHR1, (ii) the multi-protein complex Pol II-GFP and (iii) the soluble protein lysozyme. Our results indicate that the concentration and diffraction quality of NCs, particularly those with high solvent content and sensitivity to mechanical manipulation may be affected by the delivery process.

Combustion for the Synthesis of β-SiC and Diamond/SiC Composite

1993 ◽  
Vol 327 ◽  
Author(s):  
Rohini Raghunathan ◽  
Rina Chowdhury ◽  
Jagdish Narayan
Keyword(s):  
Electron Microscopy ◽  
Exothermic Reaction ◽  
Diamond Films ◽  
Temperature Synthesis ◽  
X Ray ◽  
High Temperature Synthesis ◽  
Transmission Electron ◽  
Set Up ◽  
Spectroscopy Studies

AbstractCubic β-SiC was processed under conditions of self-propagating high-temperature synthesis, based on the exothermic reaction between elemental Si and C powders. The set up for the synthesis of SiC using a mixture of Si and C is described. X-Ray and Raman spectroscopy studies were performed to characterize the quality of the β-SiC produced using the new set up. Scanning Electron Microscopy and Transmission Electron Microscopy studies were also carried out to study the mechanism of the formation of β-SiC from the elemental powders. The density of the compact and grain size of the graphite was found to be critical in the formation of the SiC. Diamond seeds were also implanted on the SiC pellet while compaction and this implanted diamond provided the necessary seed for the growth of a thick diamond film. The adhesion of the film is good because of its growth from the implanted diamond. Diamond films were grown on SiC using HFCVD. The quality and the adhesion of the diamond films on SiC were studied using SEM.

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