Stress‐Induced Dark Line Defect Formation in GaAlAs : Si LED's

1981 ◽  
Vol 128 (3) ◽  
pp. 661-669 ◽  
Author(s):  
A. K. Chin ◽  
W. C. King ◽  
T. J. Leonard ◽  
R. J. Roedel ◽  
C. L. Zipfel ◽  
...  
Keyword(s):  
Defect Formation ◽  
Line Defect ◽  
Dark Line

Strain-Relieved Reliable Lasers Grown on Si By MOCVD

1992 ◽  
Vol 281 ◽  
Author(s):  
Takashi Egawa ◽  
Yoshiaki Hasegawa ◽  
Takashi Jimbo ◽  
Masayoshi Umeno
Keyword(s):  
Intermediate Layer ◽  
Defect Formation ◽  
Laser Diodes ◽  
Electrical Characteristics ◽  
Line Defect ◽  
Dark Line ◽  
Si Substrates ◽  
Forward Current ◽  
Current Voltage ◽  
Line Defects

ABSTRACTConventional GaAs-based laser diodes grown on Si substrates suffer from rapid degradation, which results from the deteriorations of optical and electrical characteristics. Electroluminescence observation shows that the optical deterioration is caused by the formation of dark-line defects. The current-voltage (I-V) characteristic of the p-n junction is degraded with aging, and results in an ohmic-like under a higher ambient temperature and a larger forward current. The deterioration of the I-V characteristic is caused by defect-accelerated impurity diffusion because the growth of GaAs on Si substrates (GaAs/Si) involves the high dislocation density, the large tensile stress and the large amount of Si near the GaAs/Si interface. A significant improvement in reliability has been achieved in the strain-relieved AlGaAs/InGaAs laser diode on Si grown with the InGaAs intermediate layer. The stress relief by the InGaAs active layer and the reduction of the dark-line defect formation by the InGaAs intermediate layer are required to fabricate reliable GaAs-based laser diodes on Si substrates.

Inhibited dark-line defect formation in strained InGaAs/AlGaAs quantum well lasers

1990 ◽  
Vol 2 (8) ◽  
pp. 531-533 ◽  
Author(s):  
R.G. Waters ◽  
D.P. Bour ◽  
S.L. Yellen ◽  
N.F. Ruggieri
Keyword(s):  
Quantum Well ◽  
Defect Formation ◽  
Quantum Well Lasers ◽  
Line Defect ◽  
Dark Line

Rapid degradation of InGaAsP/InP double heterostructure lasers due to 〈110〉 dark line defect formation

1982 ◽  
Vol 40 (11) ◽  
pp. 921-923 ◽  
Author(s):  
K. Endo ◽  
S. Matsumoto ◽  
H. Kawano ◽  
I. Sakuma ◽  
T. Kamejima
Keyword(s):  
Defect Formation ◽  
Line Defect ◽  
Dark Line ◽  
Rapid Degradation ◽  
Double Heterostructure

Native Point Defect Densities and Dark Line Defects in ZnSe

1995 ◽  
Vol 408 ◽  
Author(s):  
M. A. Berding ◽  
A. Sher ◽  
M. Van Schilfgaarde
Keyword(s):  
Free Energy ◽  
Point Defect ◽  
Defect Formation ◽  
Local Density ◽  
Full Potential ◽  
Nonradiative Recombination ◽  
Dark Line ◽  
Frenkel Defect ◽  
Native Point Defect ◽  
Defect Densities

AbstractNative point defect densities (including vacancies, antisites and interstitials) in ZnSe are calculated using a quasichemical formalism, including both vibrational and electronic contributions to the defect free energy. The electronic contribution to the defect formation free energy is calculated using the self-consistent first-principles full-potential linearized muffin-tin orbital (FP-LMTO) method and the local-density approximation (LDA). Gradient corrections are included so that absolute reference to zinc atoms in the vapor phase can be made. We find that the Frenkel defect formation energy is ∼0.3 eV lower at a stacking fault than in the bulk lattice. Nonradiative-recombination-induced Frenkel defect generation at stacking faults is proposed as a mechanism responsible for the limited device lifetimes.

scholarly journals Forming and Properties of Friction Stir Welding Process for Dissimilar Mg Alloy

2015 ◽  
Vol 9 (1) ◽  
pp. 859-864
Author(s):  
Tielong Li ◽  
Zhenshan Wang
Keyword(s):  
Magnesium Alloy ◽  
Process Parameters ◽  
Welded Joints ◽  
Defect Formation ◽  
Base Material ◽  
Welding Process ◽  
Fracture Initiation ◽  
Line Defect ◽  
Influence Of Process Parameters ◽  
Friction Stir

For hot extrusions of magnesium alloy sheets, Dissimilar AZ80 and AZ31 were used, in which AZ80 was placed on advancing side and AZ31 on retreating side, using friction stir butt welding with different process parameters. Some defect-free welded joints with good weld surfaces could be obtained with some suitable welding conditions. The maximum tensile strength of welded joint which is 225.5 MPa can reach 98% that of the AZ31 base material. Influence of process parameters on defects, weld shaping and mechanical property were discussed systematically. And the microstructure of different zones was compared. The fracture of the welded joints takes place at the junction of mechanical heat affected zone and nugget zone in AZ31 magnesium alloy set retreating side, since existing difference in metallographic structure of alloy diversely suffered by heat, pressure and depositing impurities. Fracture initiation site may be the P line defect which should be eliminated, and the P line defect formation was analyzed.

Modeling the Effect of Temperature-Induced Surface Tension Gradient in Coating Processes

2014 ◽  
Vol 917 ◽  
pp. 181-188
Author(s):  
Bawadi Abdullah ◽  
Dai Viet N. Vo ◽  
Sujan Chowdhury
Keyword(s):  
Surface Tension ◽  
Defect Formation ◽  
Process Analysis ◽  
Industrial Applications ◽  
Effect Of Temperature ◽  
Surface Tension Gradient ◽  
Analysis Tool ◽  
Navier Stokes Equation ◽  
Dark Line ◽  
Fluorescent Tube

The coating of the fluorescent-lamp material inside the fluorescent tube is prone to defect such as dark line formation. A one-dimensional mathematical model based on Navier-Stokes equation, which describes the flow of drying coating on horizontal planar substrates, was developed to investigate the defect formation. The effect of temperature distribution on surface tension gradient was incorporated into the model, to quantify defect formation in drying coating. The results showed that, temperature-induced surface tension gradient plays a major role in defect formation while the effect of pressure gradient is insignificant. The evaporation rate and viscosity affect the defect thickness and spread, and also the defect formation time. The temperature gradient seems to have the largest influence on surface tension gradient, thus defect formation. The model developed can be used as a process analysis tool in industrial applications of fluorescent tube coating.

STEM-HAADF electron microscopy analysis of the central dark line defect of human tooth enamel crystallites

2007 ◽  
Vol 19 (2) ◽  
pp. 877-882 ◽  
Author(s):  
Jose Reyes Gasga ◽  
Georgina Carbajal-de-la-Torre ◽  
Etienne Bres ◽  
Ivet M. Gil-Chavarria ◽  
Ana G. Rodríguez-Hernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Tooth Enamel ◽  
Human Tooth ◽  
Line Defect ◽  
Dark Line ◽  
Human Tooth Enamel ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis
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