Growth and Characterization of InP/GaAs on Soi by Mocvd

1990 ◽  
Vol 198 ◽  
Author(s):  
N.H. Karam ◽  
V. Haven ◽  
S.M. Vernon ◽  
F. Namavar ◽  
N. El-Masry ◽  
...  
Keyword(s):  
Thermal Cycle ◽  
Defect Density ◽  
Photoluminescence Intensity ◽  
Defect Reduction ◽  
Reduction Techniques ◽  
Thermal Cycle Annealing ◽  
Cycle Growth ◽  
Order Of Magnitude ◽  
First Time

ABSTRACTEpitaxial InP films have been successfully deposited on GaAs coated silicon wafers with a buried oxide for the first time by MOCVD. The SOI wafers were prepared using the Separation by IMplantation of Oxygen (SIMOX) process. The quality of InP on SIMOX is comparable to the best of InP on Si deposited in the same reactor. Preliminary results on defect reduction techniques such as Thermal Cycle Growth (TCG) show an order of magnitude increase in the photoluminescence intensity and a factor of five reduction in the defect density. TCG has been found more effective than Thermal Cycle Annealing (TCA) in improving the crystalline perfection and optical properties of the deposited films.

Defect Reduction of Cvd-Grown Cubic SiC Epitaxial Films on Off-Axis Si(100) Substrates with a Novel Off-Direction.

1990 ◽  
Vol 198 ◽  
Author(s):  
Katsuki Furukawa ◽  
Yoshihisa Fujii ◽  
Akira Suzuki ◽  
Shigeo Nakajima
Keyword(s):  
Defect Density ◽  
Chemical Vapor ◽  
Epitaxial Films ◽  
Defect Reduction ◽  
Fault Density ◽  
Electrolytic Etching ◽  
Order Of Magnitude ◽  
First Time ◽  
Defect Densities ◽  
Sic Films

ABSTRACTMonocrystalline cubic SiC (β -SiC) thin films with lower defect densities have been epitaxially grown by chemical vapor deposition on off-axis Si (100) substrates with off-directions different from the conventional 〈011〉. Stacking faults of β -SiC films are investigated by the electrolytic etching and SEM observation. The effects of off-direction deviated from 〈011〉 are examined for the first time. The off-angle is fixed at 2 degrees. We find a reduction in defect density with increasing deviation angle θ, of off-direction from [011] toward [011[ (θ = 0 - 45°). The defect density becomes one order of magnitude smaller than that of on-axis (100) substrates. A typical value of the stacking fault density is approximately 6 × 106 cm−2 on the substrate with θ = 30° (film thickness: 24μ m).

High Quality GaAs on Soi by MOCVD

1989 ◽  
Vol 160 ◽  
Author(s):  
N.H. Karam ◽  
V. Haven ◽  
S. Vernon ◽  
J. Ramdani ◽  
N. El-Masry ◽  
...  
Keyword(s):  
Thermal Cycle ◽  
Defect Density ◽  
Fold Increase ◽  
Gate Length ◽  
Photoluminescence Intensity ◽  
Large Area ◽  
High Quality ◽  
Cycle Growth ◽  
Gaas Films ◽  
Low Temperature Photoluminescence

AbstractEpitaxial GaAs films have been successfully deposited on three-inch Si wafers with a buried oxide by MOCVD. The SOI wafers were prepared using Separation by IMplantation of OXygen (SIMOX) process. High quality GaAs on SIMOX films, with dislocation density in the range of 2–6 × 106 cm-2, have been achieved using Thermal Cycle Growth (TCG) deposition technique. These films showed a 50-fold increase in the low temperature photoluminescence intensity over conventional deposition. We have also fabricated MESFET’s in GaAs on SIMOX with performance comparable to those fabricated in GaAs. The maximum measured transconductance was in the range of 175-180 ms/mm at a 1.5 µm gate length and a 5 µm source to drain separation. This is the first demonstration of large area, high quality and low defect density GaAs on SIMOX.

Improvement of Inp-GaAs-Si Quality by Thermal-Cycle Growth

1990 ◽  
Vol 198 ◽  
Author(s):  
S.M. Vernon ◽  
C.J. Keavney ◽  
E.D. Gagnon ◽  
N.H. Karam ◽  
N.M. Haegel ◽  
...  
Keyword(s):  
Thermal Cycle ◽  
Chemical Vapor ◽  
Defect Reduction ◽  
Thermal Cycle Annealing ◽  
Transmission Electron ◽  
Cycle Growth ◽  
Crystal Films ◽  
Photoluminescence Lifetime ◽  
Hall Effect Measurements ◽  
Inp Substrates

ABSTRACTSingle-crystal films of InP have been deposited on GaAs, GaAs-coated Si, and InP substrates by metalorganic chemical vapor deposition (MOCVD). Defect-reduction schemes involving various thermal annealing recipes have been developed and characterized. Material quality has been assessed by a variety of methods including transmission electron microscopy, X-ray rocking curve analysis, low-temperature photoluminescence, lifetime measurements, Hall-effect measurements, electrochemical profiling, and Nomarski microscopy. The use of either a thermal-cycle-growth or a thermal-cycle-annealing process leads to heteroepitaxial InP film quality which is significantly improved over that of its as-grown state, with the thermal-cycle growth appearing to be the more effective technique.

Effects of thermal cycle annealing on reduction of defect density in lattice-mismatched InGaAs solar cells

2006 ◽  
Vol 376-377 ◽  
pp. 626-629 ◽  
Author(s):  
T. Sasaki ◽  
K. Arafune ◽  
H.S. Lee ◽  
N.J. Ekins-Daukes ◽  
S. Tanaka ◽  
...  
Keyword(s):  
Solar Cells ◽  
Thermal Cycle ◽  
Defect Density ◽  
Thermal Cycle Annealing

scholarly journals Characterization of the ECN spray A in different facilities. Part 1: boundary conditions characterization

2020 ◽  
Vol 75 ◽  
pp. 35
Author(s):  
Moez Ben Houidi ◽  
Camille Hespel ◽  
Michele Bardi ◽  
Ob Nilaphai ◽  
Louis-Marie Malbec ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Internal Combustion Engines ◽  
Operating Mode ◽  
Wall Layer ◽  
Time Resolved ◽  
Order Of Magnitude ◽  
Experimental Facilities ◽  
Proper Estimation ◽  
First Time

The Engine Combustion Network (ECN) community has greatly contributed to improve the fundamental understanding of spray atomization and combustion at conditions relevant to internal combustion engines. In this context, standardized spray experiments have been defined to facilitate the comparison of experimental and simulation studies performed in different facilities and with different models. This operating mode promotes collaborations among research groups and accelerates the advancement of research on spray. In efforts to improve the comparability of the ECN spray A experiments, it is of high importance to review the boundary conditions of different devices used in the community. This work is issued from the collaboration in the ECN France project, where two new experimental facilities from PPRIME (Poitiers) and PRISME (Orleans) institutes are validated to perform spray A experiments. The two facilities, based on Rapid Compression Machine (RCM) design, have been investigated to characterize their boundary conditions (e.g., flow velocity as well as fuel and gas temperatures). A set of standardized spray experiments were performed to compare their results with those obtained in other facilities, in particular the Constant Volume Pre-burn (CVP) vessel at IFPEN. It is noteworthy that it is the first time that RCM type facilities are used in such a way within the ECN. This paper (part 1) focuses on the facilities description and the fine characterization of their boundary conditions. A further paper (part 2) will present the results obtained with the same facilities performing ECN standard spray A characterizations. The reported review of thermocouple thermometry highlights that it is necessary to use thin-wires and bare-bead junction as small as possible. This would help to measure the temperature fluctuations with a minimal need for error corrections, which are highly dependent on the proper estimation of the velocity through the junction, and therefore it may introduce important uncertainties. Temperature heterogeneities are observed in all spray A devices. The standard deviation of the temperature distribution at the time of injection is approximately 5%. We report time-resolved temperature measurement from PPRIME RCM, performed in the near nozzle area during the injection. In inert condition, colder gases from the boundary layer are entrained toward the mixing area of the spray causing a further deviation from the target temperature. This emphasizes the importance of the temperature in the boundary (wall) layer. In reacting condition, the temperature of these entrained gases increases by the effect of the increased pressure, as the RCM has a relatively small volume. Generally, the velocity and turbulence levels are an order of magnitude higher in RCM and constant pressure flow compared to CVP vessels. The boundary characterization presented here will be the base for discussing spray behavior in the part 2 of this paper.

Structural and optical characterization of InP grown on Si(111) by metalorganic vapor phase epitaxy using thermal cycle growth

1996 ◽  
Vol 80 (9) ◽  
pp. 4997-5005 ◽  
Author(s):  
Y. Ababou ◽  
P. Desjardins ◽  
A. Chennouf ◽  
R. Leonelli ◽  
D. Hetherington ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Thermal Cycle ◽  
Optical Characterization ◽  
Metalorganic Vapor Phase Epitaxy ◽  
Vapor Phase Epitaxy ◽  
Cycle Growth

Reduction of Defect Density in Structures With InAs-GaAs Quantum Dots Grown at Low Temperature for 1.55 [.proportional]m Range.

2001 ◽  
Vol 672 ◽  
Author(s):  
N.D. Zakharov ◽  
P. Werner ◽  
U. Gösele ◽  
N.N. Ledentsov ◽  
D. Bimberg ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Defect Density ◽  
Gaas Layer ◽  
Defect Reduction ◽  
Inas Quantum Dots ◽  
Reduction Techniques ◽  
Growth Interruption ◽  
Gaas Matrix ◽  
Transmission Electron ◽  
Local Defects

ABSTRACTTransmission electron microscopy (TEM), and photoluminescence (PL) have been used to evaluate defects and the efficiency of defect-reduction techniques in structures with InAs quantum dots (QDs) for the 1.55 µm range grown at low substrate temperature (LT) using molecular beam epitaxy (MBE). We show that capping of the QDs with thin GaAs layer accompanied by growth interruption at 600oC (flash) allows to eliminate large islands, containing dislocations, while the smaller islands containing local defects (e.g. dislocation dipoles) still remain. If the flash procedure is accompanied with further depositing of thin AlAs cap layer, and followed by high temperature (~700oC) annealing (HTA), an almost complete elimination of defects is observed. The structures emit in the range of 1.55 µm due to lateral agglomerates of LTQDs. Simultaneously bright luminescence due to isolated QDs and GaAs matrix are detected at high excitation densities.

TBE in Sweden

2020 ◽  
Keyword(s):  
Genetic Characterization ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Second Phase ◽  
Serum Samples ◽  
Tick Borne Encephalitis ◽  
Specific Immunoglobulin ◽  
Tick Borne Encephalitis Virus ◽  
First Time

Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.

Chemical Constituents and Antibacterial Activity of Cissus Aralioides.

2020 ◽  
Vol 17 ◽  
Author(s):  
Balogun Olaoye Solomon ◽  
Ajayi Olukayode Solomon ◽  
Owolabi Temitayo Abidemi ◽  
Oladimeji Abdulkarbir Oladele ◽  
Liu Zhiqiang
Keyword(s):  
Plant Extract ◽  
Chemical Constituents ◽  
Ethyl Acetate Fraction ◽  
Antibacterial Activities ◽  
Sub Saharan Africa ◽  
Chromatographic Purification ◽  
Whole Plant ◽  
Sub Saharan ◽  
First Time

: Cissus aralioides is a medicinal plant used in sub-Saharan Africa for treatment of infectious diseases; however the chemical constituents of the plant have not been investigated. Thus, in this study, attempt was made at identifying predominant phytochemical constituents of the plant through chromatographic purification and silylation of the plant extract, and subsequent characterization using spectroscopic and GC-MS techniques. The minimum inhibitory concentration (MICs) for the antibacterial activities of the plant extract, chromatographic fractions and isolated compounds were also examined. Chromatographic purification of the ethyl acetate fraction from the whole plant afforded three compounds: β-sitosterol (1), stigmasterol (2) and friedelin (3). The phytosterols (1 and 2) were obtained together as a mixture. The GC-MS analysis of silylated extract indicated alcohols, fatty acids and sugars as predominant classes, with composition of 24.62, 36.90 and 26.52% respectively. Results of MICs indicated that friedelin and other chromatographic fractions had values (0.0626-1.0 mg/mL) comparable with the standard antibiotics used. Characterization of natural products from C. aralioides is being reported for the first time in this study.

Green Synthesis and Spectroscopic Studies of Ag-rGO Nanocomposites for Highly Selective Mercury (II) Sensing

2018 ◽  
Vol 9 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Shubhangi J. Mane-Gavade ◽  
Sandip R. Sabale ◽  
Xiao-Ying Yu ◽  
Gurunath H. Nikam ◽  
Bhaskar V. Tamhankar
Keyword(s):  
Green Synthesis ◽  
Color Change ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Suitable Condition ◽  
Cost Effective ◽  
Spectroscopic Studies ◽  
Calibration Plot ◽  
First Time

Introduction: Herein we report the green synthesis and characterization of silverreduced graphene oxide nanocomposites (Ag-rGO) using Acacia nilotica gum for the first time. Experimental: We demonstrate the Hg2+ ions sensing ability of the Ag-rGO nanocomposites form aqueous medium. The developed colorimetric sensor method is simple, fast and selective for the detection of Hg2+ ions in aqueous media in presence of other associated ions. A significant color change was noticed with naked eye upon Hg2+ addition. The color change was not observed for cations including Sr2+, Ni2+, Cd2+, Pb2+, Mg2+, Ca2+, Fe2+, Ba2+ and Mn2+indicating that only Hg2+ shows a strong interaction with Ag-rGO nanocomposites. Under the most suitable condition, the calibration plot (A0-A) against concentration of Hg2+ was linear in the range of 0.1-1.0 ppm with a correlation coefficient (R2) value 0.9998. Results & Conclusion The concentration of Hg2+ was quantitatively determined with the Limit of Detection (LOD) of 0.85 ppm. Also, this method shows excellent selectivity towards Hg2+ over nine other cations tested. Moreover, the method offers a new cost effective, rapid and simple approach for the detection of Hg2+ in water samples.

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