Characterization of Electronic Properties of Different SiC Polytypes by All-Optical Means

2008 ◽  
Vol 600-603 ◽  
pp. 509-512 ◽  
Author(s):  
K. Neimontas ◽  
Kęstutis Jarašiūnas ◽  
Rositza Yakimova ◽  
Mikael Syväjärvi ◽  
Gabriel Ferro
Keyword(s):  
Carrier Lifetime ◽  
Carrier Dynamics ◽  
Carrier Injection ◽  
Defect States ◽  
Optical Carrier ◽  
Temperature Range ◽  
All Optical ◽  
Bimolecular Recombination ◽  
Opposite Tendency

We applied a picosecond transient grating technique for studies of nonequilibrium carrier dynamics in differently grown or doped SiC polytypes. Optical carrier injection in 4H-SiC at two different wavelengths (266 and 355 nm) allowed us to vary the depth of the photoexcited region and determine photoelectric parameters of high density (from ~1016 to ~1019 cm-3) carrier plasma in the temperature range 10 – 300 K. A strong decrease of carrier lifetime with increasing nonequlibrium carrier density was found in 4H-SiC samples at 300 K and fitted by bimolecular recombination with coefficient B = 3 × 10-11 cm3 s-1. In 3C-SiC epilayers, the opposite tendency was observed over a wide temperature range and attributed to recharging of defect states.

Optical Characterization of Compensating Defects in Cubic SiC

2013 ◽  
Vol 740-742 ◽  
pp. 401-404
Author(s):  
Patrik Ščajev ◽  
K. Jarašiūnas ◽  
P.L. Abramov ◽  
S.P. Lebedev ◽  
A.A. Lebedev
Keyword(s):  
Carrier Density ◽  
Nonlinear Optical ◽  
Carrier Lifetime ◽  
Optical Trap ◽  
Optical Characterization ◽  
Carrier Dynamics ◽  
Time Resolved ◽  
Carrier Recombination ◽  
P Type

We present investigation of carrier recombination and optical trap recharge in sublimation grown n- and p-type 3C layers by using time-resolved nonlinear optical techniques. Carrier lifetime and recharged trap recovery were measured by differential transmittivity technique. By monitoring nonequilibrium carrier dynamics, we analyzed impact of carrier density and temperature on carrier lifetime and recharged trap recovery rate. Large carrier lifetime and small diffusivity at low injections in highly compensated samples and their dependences on injection were explained by optical recharge of compensating aluminum impurities. The complete recharge of the compensating impurities by optical means allowed us to calculate the compensating aluminum density in n-type samples and compensating nitrogen in p-type ones.

Electrical Characteristics of GaAs Implanted with High Energy (100 MeV) 28Si and 120Sn Ions

2014 ◽  
Vol 661 ◽  
pp. 3-7
Author(s):  
Yousuf Pyar Ali ◽  
Arun M. Narsale ◽  
Brij Mohan Arora
Keyword(s):  
Electrical Conduction ◽  
Conduction Mechanism ◽  
Electrical Characterization ◽  
High Energy ◽  
The Other ◽  
Electrical Characteristics ◽  
Defect States ◽  
Temperature Range ◽  
Current Voltage

In this work we carried out electrical characterization of n-GaAs implanted at 300 K with high energy (100 MeV)28Si and120Sn ions to a fluence of 1x1018ions/m2using current–voltage (I-V) measurements. The as implanted samples and samples annealed in the temperature range 373-1123 K have been investigated. Resistance of the samples obtained from I-V curves recorded over the temperature range 110K-270K indicate that the samples implanted with28Si and annealed up to 623 K and the samples implanted with120Sn and annealed up to 723K shows tunnel assisted hoping conduction mechanism. In the other hand,28Si implanted samples annealed to 723K and 823K and120Sn implanted samples annealed to 823K and 923K the electrical conduction mechanism is dominated by thermal hoping between closed defect states.

scholarly journals Isolation and characterization of a new cold-active protease from psychrotrophic bacteria of Western Himalayan glacial soil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saleem Farooq ◽  
Ruqeya Nazir ◽  
Shabir Ahmad Ganai ◽  
Bashir Ahmad Ganai
Keyword(s):  
Specific Activity ◽  
Temperature Range ◽  
Psychrotrophic Bacteria ◽  
Isolation And Characterization ◽  
Cold Active ◽  
Active Protease ◽  
Quantitative Screening ◽  
First Time ◽  
Low K

AbstractAs an approach to the exploration of cold-active enzymes, in this study, we isolated a cold-active protease produced by psychrotrophic bacteria from glacial soils of Thajwas Glacier, Himalayas. The isolated strain BO1, identified as Bacillus pumilus, grew well within a temperature range of 4–30 °C. After its qualitative and quantitative screening, the cold-active protease (Apr-BO1) was purified. The Apr-BO1 had a molecular mass of 38 kDa and showed maximum (37.02 U/mg) specific activity at 20 °C, with casein as substrate. It was stable and active between the temperature range of 5–35 °C and pH 6.0–12.0, with an optimum temperature of 20 °C at pH 9.0. The Apr-BO1 had low Km value of 1.0 mg/ml and Vmax 10.0 µmol/ml/min. Moreover, it displayed better tolerance to organic solvents, surfactants, metal ions and reducing agents than most alkaline proteases. The results exhibited that it effectively removed the stains even in a cold wash and could be considered a decent detergent additive. Furthermore, through protein modelling, the structure of this protease was generated from template, subtilisin E of Bacillus subtilis (PDB ID: 3WHI), and different methods checked its quality. For the first time, this study reported the protein sequence for psychrotrophic Apr-BO1 and brought forth its novelty among other cold-active proteases.

All-optical switching in microring devices by carrier injection

2003 ◽  
Author(s):  
T.A. Ibrahim ◽  
W. Cao ◽  
Y. Kim ◽  
J. Goldhar ◽  
P.-T. Ho ◽  
...  
Keyword(s):  
Optical Switching ◽  
Carrier Injection ◽  
All Optical ◽  
All Optical Switching

Azo-containing asymmetric bent-core liquid crystals with modulated smectic phases

RSC Advances ◽  
2015 ◽  
Vol 5 (80) ◽  
pp. 64886-64891 ◽  
Author(s):  
Nemanja Trišović ◽  
Jelena Antanasijević ◽  
Tibor Tóth-Katona ◽  
Michal Kohout ◽  
Miroslaw Salamonczyk ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Synthesis And Characterization ◽  
Temperature Range ◽  
Smectic Phases ◽  
Potential Applications

We present the synthesis and characterization of ten asymmetric bent-core liquid crystals with enantiotropic modulated smectic (B7 type) phases. Their relatively low and wide photosensitive mesomorphic temperature range offers potential applications.

Electrical characterization of deep defect states in Galliumnitride co-implanted with magnesium and sulfur ions

2002 ◽  
Vol 93 (1-3) ◽  
pp. 85-89 ◽  
Author(s):  
A Krtschil ◽  
A Kielburg ◽  
H Witte ◽  
A Krost ◽  
J Christen ◽  
...  
Keyword(s):  
Electrical Characterization ◽  
Defect States ◽  
Deep Defect

Characterization of All-Optical Regeneration Potentials of a Bistable Semiconductor Ring Laser

2009 ◽  
Vol 27 (19) ◽  
pp. 4233-4240 ◽  
Author(s):  
Bei Li ◽  
M.I. Memon ◽  
G. Mezosi ◽  
Zhuoran Wang ◽  
M. Sorel ◽  
...  
Keyword(s):  
Ring Laser ◽  
All Optical ◽  
Optical Regeneration ◽  
Semiconductor Ring Laser

Development of High-Performance GaAs Solar Cells on Large-Grain Polycrystalline Ge Substrates

1995 ◽  
Vol 403 ◽  
Author(s):  
R. Venkatasubramanian ◽  
B. O'Quinn ◽  
J. S. Hills ◽  
M. L. Timmons ◽  
D. P. Malta
Keyword(s):  
Solar Cells ◽  
High Performance ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Cross Sectional ◽  
Plan View ◽  
Electron Beam Induced Current ◽  
Induced Defects

AbstractThe characterization of MOCVD-grown GaAs-AlGaAs materials and GaAs p+n junctions on poly-Ge substrates is presented. Minority carrier lifetime in GaAs-AIGaAs double-hetero (DH) structures grown on these substrates and the variation of lifetimes across different grainstructures are discussed. Minority-carrier diffusion lengths in polycrystalline GaAs p+-n junctions were evaluated by cross-sectional electron-beam induced current (EBIC) scans. The junctions were also studied by plan-view EBIC imaging. Optimization studies of GaAs solar cell on poly-Ge are discussed briefly. The effect of various polycrystalline substrate-induced defects on performance of GaAs solar cells are presented.

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