A Model for Double Positioning Twin Formation in Cubic SiC on Noncubic SiC Substrates

1992 ◽  
Vol 280 ◽  
Author(s):  
Woo Sik Yoo ◽  
Charles P. Beetz. ◽  
Fen-Ren Chien ◽  
Steven R. Nutt ◽  
Tsunenobu Kimoto ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Coulomb Force ◽  
High Energy ◽  
Electrostatic Model ◽  
Chemical Vapor Deposition Growth ◽  
Growth Simulation ◽  
Transmission Electron ◽  
Energetic Balance ◽  
Twin Formation ◽  
The Difference

ABSTRACTAs an attempt to explain polytype formation and crystal growth of SiC we propose an electrostatic model in which electrostatic Coulomb force is considered as an interatomic force. The dependence of surface potential on the stacking sequence of atoms in substrates was investigated, and the growth simulation was tried considering the energetic balance under various interaction lengths.The model predicts the double positioning twin formation and the difference in area between twins in cubic 3C-SiC growth on hexagonal 6H-SiC and rhombohedral 15R-SiC substrates. The prediction was experimentally tested by simultaneous chemical vapor deposition growth on basal planes of 6H-SiC(0001) and 15R-SiC(0001). Polytype and interface structure of both specimens were investigated by reflection high energy electron diffraction (RHEED) and high resolution transmission electron microscopy (HRTEM).

AlxGa1-xN-Based Materials and Heterostructures

1996 ◽  
Vol 449 ◽  
Author(s):  
P. Kung ◽  
A. Saxler ◽  
D. Walker ◽  
X. Zhang ◽  
R. Lavado ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Bragg Reflectors ◽  
X Ray Diffraction ◽  
Chemical Vapor Deposition Growth ◽  
X Ray ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Dimensional Electron Gas ◽  
P Type

ABSTRACTWe present the metalorganic chemical vapor deposition growth, n-type and p-type doping and characterization of AlxGa1-xN alloys on sapphire substrates. We report the fabrication of Bragg reflectors and the demonstration of two dimensional electron gas structures using AlxGa1-xN high quality films. We report the structural characterization of the AlxGa1-xN / GaN multilayer structures and superlattices through X-ray diffraction and transmission electron microscopy. A density of screw and mixed threading dislocations as low as 107 cm-2 was estimated in AlxGa1-xN / GaN structures. The realization of AlxGa1-xN based UV photodetectors with tailored cut-off wavelengths from 365 to 200 nm are presented.

scholarly journals Growth Mechanism of SmB6 Nanowires Synthesized by Chemical Vapor Deposition: Catalyst-Assisted and Catalyst-Free

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1062
Author(s):  
Yi Chu ◽  
Yugui Cui ◽  
Shaoyun Huang ◽  
Yingjie Xing ◽  
Hongqi Xu
Keyword(s):  
Chemical Vapor Deposition ◽  
Growth Mechanism ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Element Analysis ◽  
Kondo Insulator ◽  
Catalyst Free ◽  
Transmission Electron ◽  
The Difference ◽  
Physical Phenomena

SmB6 nanowires, as a prototype of nanostructured topological Kondo insulator, have shown rich novel physical phenomena relating to their surface. Catalyst-assisted chemical vapor deposition (CVD) is a common approach to prepare SmB6 nanowires and Ni is the most popular catalyst used to initiate the growth of SmB6 nanowires. Here, we study the effect of growth mechanism on the surface of SmB6 nanowires synthesized by CVD. Two types of SmB6 nanowires are obtained when using Ni as the catalyst. In addition to pure SmB6 nanowires without Ni impurity, a small amount of Ni is detected on the surface of some SmB6 nanowires by element analysis with transmission electron microscopy. In order to eliminate the possible distribution of Ni on nanowire surface, we synthesize single crystalline SmB6 nanowires by CVD without using catalyst. The difference between catalyst-assisted and catalyst-free growth mechanism is discussed.

Raman Analysis Of AlxGa1-xN Films

1997 ◽  
Vol 482 ◽  
Author(s):  
Leah Bergman ◽  
Mitra Dutta ◽  
Michael D. Bremser ◽  
Ok-Hyun Nam ◽  
William G. Perry ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Alloy System ◽  
High Energy ◽  
Line Broadening ◽  
Model Calculations ◽  
Raman Analysis ◽  
Thermal Expansion Coefficients ◽  
X Ray Scattering ◽  
The Difference ◽  
Superlattice Line

AbstractRaman analysis of the E2 mode of AlxGal-xN in the composition range 0 ≤ x ≤ 1 is presented. The lineshape was observed to exhibit a significant asymmetry and broadening toward the high energy range. The spatial correlation model is discussed, and is shown to account for the lineshape. The model calculations also indicate the lack of a long-range order in the CVD (chemical vapor deposition) alloys. These results were confirmed by X-ray scattering: the relative intensity of the superlattice line was found to be negligible. The line broadening of the E2 mode was found to exhibit a maximum at a composition x∼0.5 indicative of a random disordered alloy system. The stress state of the alloys was found to be tensile and was attributed to the difference in the thermal expansion coefficients of the SiC substrate and the film.

Suppression of the Twin Formation in CVD Growth of (111) 3C-SiC on (110) Si Substrate

2005 ◽  
Vol 483-485 ◽  
pp. 193-196 ◽  
Author(s):  
Taro Nishiguchi ◽  
Mitsutaka Nakamura ◽  
Koji Nishio ◽  
Toshiyuki Isshiki ◽  
Satoru Ohshima ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Chemical Vapor ◽  
Electron Microscopic Observation ◽  
Si Substrate ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Transmission Electron Microscopic Observation ◽  
Transmission Electron Microscopic ◽  
Cvd Growth ◽  
Twin Formation

Chemical vapor deposition of (111) 3C-SiC on (110) Si substrate was carried out, and the effect of the substrate off-axis introduced on (110) Si substrate for suppressing the twin formation in 3C-SiC hetero-epitaxial layers was investigated. From the growth on hemispherically polished (110) Si substrate, it was found that the off-axis toward the [001] Si axis had a noble effect for suppressing the twin formation, while the off-axis toward the [110] Si axis was ineffective. The growth of single 3C-SiC crystal containing few double positioning boundaries, which are related with the twin formation, was demonstrated on the (110) Si substrate 3° off-axis toward the [001] Si axis. Transmission electron microscopic observation revealed that double positioning boundaries on the (110) Si substrate off-axis toward the [001] Si axis were nearly eliminated within the initial a few hundreds nano meter in thickness.

scholarly journals Origins of Twinned Microstructures in B12As2 Epilayers Grown on (0001) 6H-SiC and Their Influence on Physical Properties

2009 ◽  
Vol 1164 ◽  
Author(s):  
Yu Zhang ◽  
Hui Chen ◽  
Ning Zhang ◽  
Michael Dudley ◽  
Yinyan Gong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Vapor Deposition ◽  
Defect Structure ◽  
Chemical Vapor ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
The Difference ◽  
The Relationship ◽  
Measured Thermal Conductivity

AbstractThe defect structure in B12As2 epitaxial layers grown at two different temperatures on (0001) 6H-SiC by chemical vapor deposition (CVD) was studied using synchrotron white beam x-ray topography (SWBXT) and high resolution transmission electron microscopy (HRTEM). The observed differences in microstructures were correlated with the differences in nucleation at the two growth temperatures. The effect of the difference in microstructure on macroscopic properties of the B12As2 was illustrated using the example of thermal conductivity which was measured using the 3-ω technique. The relationship between the measured thermal conductivity and observed microstructures is discussed.

Amplification Path Length Dependence Studies of Stimulated Emission from Optically Pumped InGaN/GaN Multiple Quantum Wells

1998 ◽  
Vol 537 ◽  
Author(s):  
T.J. Schmidt ◽  
S. Bidnyk ◽  
Yong-Hoon Cho ◽  
A.J. Fischer ◽  
J.J. Song ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Chemical Vapor ◽  
High Energy ◽  
Stimulated Emission ◽  
Multiple Quantum Wells ◽  
Excitation Density ◽  
Multiple Quantum ◽  
Optically Pumped ◽  
Energy Peak ◽  
The Difference

AbstractOptically pumped stimulated emission (SE) from InGaN/GaN multiple quantum wells (MQWs) grown by metalorganic chemical vapor deposition has been systematically studied as a function of excitation length (Lexc). Two distinct SE peaks were observed from these structures: one that originates at 425 nm at 10 K (430 nm at 300 K) and another that originates at 434 nm at 10 K (438 nm at 300 K). The SE threshold for the high energy peak was observed to always be lower than that of the low energy peak, but the difference was found to decrease greatly with increasing Lexc. A detailed study of the emission intensity of these two SE peaks as a function of excitation density shows that the two peaks compete for gain in the MQW active region.

scholarly journals Amplification Path Length Dependence Studies of Stimulated Emission from Optically Pumped InGaN/GaN Multiple Quantum Wells

1999 ◽  
Vol 4 (S1) ◽  
pp. 757-762 ◽  
Author(s):  
T.J. Schmidt ◽  
S. Bidnyk ◽  
Yong-Hoon Cho ◽  
A.J. Fischer ◽  
J.J. Song ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Chemical Vapor ◽  
High Energy ◽  
Stimulated Emission ◽  
Multiple Quantum Wells ◽  
Excitation Density ◽  
Multiple Quantum ◽  
Optically Pumped ◽  
Energy Peak ◽  
The Difference

Optically pumped stimulated emission (SE) from InGaN/GaN multiple quantum wells (MQWs) grown by metalorganic chemical vapor deposition has been systematically studied as a function of excitation length (Lexc). Two distinct SE peaks were observed from these structures: one that originates at 425 nm at 10 K (430 nm at 300 K) and another that originates at 434 nm at 10 K (438 nm at 300 K). The SE threshold for the high energy peak was observed to always be lower than that of the low energy peak, but the difference was found to decrease greatly with increasing Lexc. A detailed study of the emission intensity of these two SE peaks as a function of excitation density shows that the two peaks compete for gain in the MQW active region.

Depth-Dependent Character of Extended Defects in Ion-Implanted and RTA'd Si

1987 ◽  
Vol 104 ◽  
Author(s):  
Rodney A. Herring
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Energy ◽  
Dislocation Network ◽  
Extended Defects ◽  
Transmission Electron ◽  
Buried Layer ◽  
The Difference ◽  
Defect Character ◽  
Ion Implanted

ABSTRACTThe character of extended defects formed in high-energy S-ion implanted and rapid thermal annealed (RTA'd) Si has been found by transmission electron microscopy (TEM) to be dependent on the depth at which the defects have formed in the ion-implanted regions. Si implanted with 6 MeV S-ions and RTA'd at 1000°C for 10 s showed a buried layer of extended defects with unfaulted loops towards the top and faulted loops towards the bottom. At higher S fluences, all the loops were unfaulted, some loops coalesced to form a dislocation network, and SiS precipitates were formed. At higher RTA temperatures, all the loops were unfaulted. A few possibilities that could explain the difference in defect character will be discussed.

Chemical Vapor Deposition Growth of Multi-Walled Carbon Nanotubes on Metallic Substrates

2007 ◽  
Vol 121-123 ◽  
pp. 101-104
Author(s):  
Xiao Ping Zou ◽  
H. Abe ◽  
Toru Shimizu ◽  
A. Ando ◽  
H. Tokumoto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Growth ◽  
Large Current ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A simple thermal chemical vapor deposition (STCVD) growth technique of multi-walled carbon nanotubes (MWCNTs) is present. Carbon nanotube film was synthesized on the Pt plate substrates by pyrolysis of ethyl alcohol as carbon source at lower reaction temperature at atmospheric pressure by using simple apparatus. The as-synthesized MWCNTs were characterized by both scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The electrical property of an individual MWCNT was evaluated by I-V measurement. The electrical resistance of single MWCNT is about 450 k/ in linear region under bias voltage between 2 to 4 V. It can undergo a large current of 6 2A at 4 V

scholarly journals Study on Chemical Vapor Deposition Growth and Transmission electron Microscopy MoS 2 /h-BN Heterostructure

2016 ◽  
Vol 22 (S3) ◽  
pp. 1640-1641 ◽  
Author(s):  
Fu Zhang ◽  
Mohammed Abu AlSaud ◽  
Mel Hainey ◽  
Ke Wang ◽  
Joan M. Redwing ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Growth ◽  
Transmission Electron
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