scholarly journals Photoluminescence of 8H-SiC

2013 ◽  
Vol 740-742 ◽  
pp. 347-350 ◽  
Author(s):  
Anne Henry ◽  
Ivan G. Ivanov ◽  
Erik Janzén ◽  
Tomoaki Hatayama ◽  
Hiroshi Yano ◽  
...  
Keyword(s):  
Binding Energy ◽  
Low Temperature ◽  
Band Gap ◽  
Free Exciton ◽  
Photoluminescence Spectroscopy ◽  
Ionization Energies ◽  
Nitrogen Levels ◽  
Excitonic Band ◽  
Exciton Recombination

8H-SiC epilayers grown on small 8H-SiC Lely platelets are investigated optically using photoluminescence spectroscopy. At low temperature the near band gap emission detected in the 2.78 to 2.67 eV range contains sharp lines associated to nitrogen-bound-exciton recombination. Three different no-phonon lines are detected accompanied by their phonon replicas. Free-exciton replicas are also observed which allows the determination of the excitonic band gap. The binding energy of the bound excitons can thus be determined and the ionization energies of the three nitrogen levels in 8H-SiC are estimated and found to be rather shallow compared to the values for other hexagonal polytypes. Additional bound-exciton lines are observed when the experimental photoluminescence temperature is increased.

Photoluminescence of 10H-SiC

2016 ◽  
Vol 858 ◽  
pp. 269-273
Author(s):  
Anne Henry ◽  
Hiroshi Yano ◽  
Tomoaki Hatayama
Keyword(s):  
Electron Microscope ◽  
Band Gap ◽  
Transmission Electron Microscope ◽  
Lower Energy ◽  
Free Exciton ◽  
Binding Energies ◽  
Photoluminescence Spectra ◽  
Transmission Electron ◽  
First Time

The photoluminescence of the near band gap emission of 10H-SiC is revealed for the first time and detected just below 3.0 eV. The crystallinity thus polytype of the sample is controlled with transmission electron microscope analyses and Laue diffraction. On the photoluminescence spectra up to eight sharp lines are associated to the non-phonon lines of the nitrogen bound exciton even if ten are expected in 10H-SiC. Phonon replicas of these non-phonon lines are observed at lower energy with energy separations similar than those in other hexagonal SiC polytypes. At moderate temperature free-exciton replicas are also observed which allow the determination of the excitonic band gap at 3020.6 meV, value in agreement with the hexagonality of 10H-SiC of 40%. The binding energies associated to the nitrogen bound-excitons are determined as well as the ionization energies of the nitrogen donors in the 10H-SiC polytype.

scholarly journals Optical determination of the band gap and band tail of epitaxial Ag2ZnSnSe4 at low temperature

2020 ◽  
Vol 102 (19) ◽  
Author(s):  
Joël Bleuse ◽  
Sylvain Perret ◽  
Yoann Curé ◽  
Louis Grenet ◽  
Régis André ◽  
...  
Keyword(s):  
Low Temperature ◽  
Band Gap ◽  
Band Tail ◽  
Optical Determination

Decay Measurements of Free and Bound Exciton Recombination in Doped GaAs/GaAIAs Quantum Wells

1989 ◽  
Vol 163 ◽  
Author(s):  
J.P. Bergman ◽  
P.O. Holtz ◽  
B. Monemar ◽  
M. Sundaram ◽  
J.L Merz ◽  
...  
Keyword(s):  
Low Temperature ◽  
Quantum Wells ◽  
Temperature Dependence ◽  
Decay Time ◽  
Free Exciton ◽  
Temperature Decay ◽  
Photoluminescence Decay ◽  
Decay Times ◽  
Exciton Recombination

AbstractIn this study we present photoluminescence decay measurements of free exciton (FE) and bound exciton (BE) recombination in doped GaAs/AIGaAs quantum wells (QW). It is found that the FE decay time is reduced in the doped QW’s compared to similar undoped samples. The low temperature decay time of the BE is slightly longer than for the FE, with BE decay times from 300 to 600 ps for well widths of 50 to 150 Å, respectively. It is also found that the observed decay of the BE is strongly influenced by the decay time of the FE. This is especially observed in the similarity of the temperature dependence for the FE and BE decay time.

Low Temperature Photoluminescence Signature of Stacking Faults in 6H-SiC Epilayers Grown on Low Angle Off-Axis Substrates

2012 ◽  
Vol 717-720 ◽  
pp. 407-410
Author(s):  
J.W. Sun ◽  
T. Robert ◽  
Valdas Jokubavicius ◽  
Sandrine Juillaguet ◽  
Rositza Yakimova ◽  
...  
Keyword(s):  
Low Temperature ◽  
Band Gap ◽  
Radiative Recombination ◽  
Stacking Faults ◽  
Photoluminescence Spectroscopy ◽  
Material Growth ◽  
Different Types ◽  
Direct Feedback ◽  
Non Destructive ◽  
Low Temperature Photoluminescence

The radiative recombination spectra of 6H-SiC epilayers grown on low angle (1.4° off-axis) substrates have been investigated by low temperature photoluminescence spectroscopy. Four different types of stacking faults have been identified, together with the presence of 3C-SiC inclusions. From the energy of the momentum-conserving phonons, four excitonic band gap energies have been found with Egx equal to 2.837, 2.698, 2.600 and 2.525 eV. These photoluminescence features, which give a rapid and non-destructive approach to identify stacking faults in 6H-SiC, provide a direct feedback to improve the material growth.

SUPERMET 2205

Alloy Digest ◽  
2004 ◽  
Vol 53 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Tensile Properties ◽  
Stainless Steels ◽  
Ferritic Stainless Steels ◽  
Nitrogen Levels ◽  
Temperature Performance ◽  
Low Temperature Performance

Abstract Supermet 2205 is a manual metal arc (MMA) electrode with enhanced chromium, molybdenum, and nitrogen levels. It is used for welding standard 22% Cr duplex austenitic/ferritic stainless steels. This datasheet provides information on composition, microstructure, hardness, and tensile properties as well as fracture toughness. It also includes information on low temperature performance as well as joining. Filing Code: SS-903. Producer or source: Metrode Products Ltd.

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