Role of substrate threading dislocation density in relaxation of highly strained InGaAs/GaAs quantum well structures

1990 ◽  
Vol 56 (14) ◽  
pp. 1350-1352 ◽  
Author(s):  
J. F. Klem ◽  
W. S. Fu ◽  
P. L. Gourley ◽  
E. D. Jones ◽  
T. M. Brennan ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Quantum Well ◽  
Threading Dislocation ◽  
Quantum Well Structures ◽  
Threading Dislocation Density ◽  
Highly Strained

Yellow-green emission for ETS-LEDs and lasers based on a strained–InGaP quantum well heterostructure grown on a transparent, compositionally graded AlInGaP buffer

2002 ◽  
Vol 744 ◽  
Author(s):  
Lisa McGill ◽  
Juwell Wu ◽  
Eugene Fitzgerald
Keyword(s):  
Dislocation Density ◽  
Quantum Well ◽  
Gallium Phosphide ◽  
Light Emitting Diodes ◽  
Green Emission ◽  
Threading Dislocation ◽  
Peak Wavelength ◽  
Device Structure ◽  
Light Emitting ◽  
Threading Dislocation Density

ABSTRACTEpitaxial-transparent-substrate light emitting diodes with a primary emission peak at 590nm and a secondary peak at 560nm have been fabricated in the indium aluminum gallium phosphide (InAlGaP) system. The active layer consists of an undoped, compressively strained indium gallium phosphide (InGaP) quantum well on a transparent In0.22(Al0.2Ga0.8)0.78P/ ∇x[1nx(Al0.2Ga0.8)1-xP] /GaP virtual substrate. Theoretical modeling of this structure predicts an accessible wavelength range of approximately 540nm to 590nm (green to amber). Emission with a peak wavelength of 570nm has been observed via cathodoluminescence studies of undoped structures with a quantum well composition of In0.35Ga0.65P. Light emitting diodes have been fabricated utilizing simple top and bottom contacts. The highest LED power of 0.18μW per facet at 20mA was observed for a quantum well composition of In0.32Ga0.68P and a bulk threading dislocation density on the order of 7×106 cm-2. The spectrum of this device was composed of two peaks: a weak peak at the predicted 560nm wavelength and a stronger peak at 590nm. Based upon superspots present in electron diffraction from the quantum well region, we believe that the observed spectrum is the result of emission from ordered and disordered domains in the active region. The same device structure grown with a bulk threading dislocation density on the order of 5×107 cm-2 exhibited an identical spectral shape with a reduced power of 0.08μW per facet at 20mA. For a quantum well composition of In0.37Ga0.63P and an overall threading dislocation density on the order of 5×107 cm-2, a single peak wavelength of 588nm with a power of 0.06μW per facet at 20mA was observed.

scholarly journals LT-AlSb Interlayer as a Filter of Threading Dislocations in GaSb Grown on (001) GaAs Substrate Using MBE

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 628
Author(s):  
Agata Jasik ◽  
Jacek Ratajczak ◽  
Iwona Sankowska ◽  
Andrzej Wawro ◽  
Dariusz Smoczyński ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Low Temperature ◽  
Dislocation Density ◽  
Gaas Substrate ◽  
Periodic Array ◽  
Crystal Quality ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Threading Dislocation Density

We report on the role of AlSb material in the reduction of threading dislocation density (TDD) in the GaSb/AlSb/GaAs system. The AlSb layers were grown using low-temperature (LT) MBE, exploiting the interfacial misfit (IMF) dislocation array. AlSb layers with four different thicknesses in the range of 1–30 nm were investigated. The results showed the inhibiting role of LT-AlSb layers in the reduction of TDD. Values of TDD as low as 2.2 × 106 and 6.3 × 106 cm−2 for samples with thin and thick AlSb layers were obtained, respectively. The filtering role of AlSb material was proven despite the IMF-AlSb/GaAs interface’s imperfectness caused by the disturbance of a 90° dislocation periodic array by, most likely, 60° dislocations. The dislocation lines confined to the region of AlSb material were visible in HRTEM images. The highest crystal quality and smoother surface of 1.0 μm GaSb material were obtained using 9 nm thick AlSb interlayer. Unexpectedly, the comparative analysis of the results obtained for the GaSb/LT-AlSb/GaAs heterostructure and our best results for the GaSb/GaAs system showed that the latter can achieve both higher crystal quality and lower dislocation density.

High-Irradiance Degradation Studies of Metamorphic 1eV GaInAs Solar Cells

2012 ◽  
Vol 1432 ◽  
Author(s):  
Ryan M. France ◽  
Myles A. Steiner
Keyword(s):  
Solar Cells ◽  
Active Region ◽  
Dislocation Density ◽  
Dark Current ◽  
Degradation Mechanism ◽  
Control Cell ◽  
High Irradiance ◽  
Threading Dislocation ◽  
Threading Dislocation Density ◽  
Degradation Studies

ABSTRACTInitial tests are performed regarding the degradation of lattice-mismatched GaInAs solar cells. 1eV metamorphic GaInAs solar cells with 1-2×106 cm-2 threading dislocation density in the active region are irradiated with an 808 nm laser for 2 weeks time under a variety of temperature and illumination conditions. All devices show a small degradation in Voc that is logarithmic with time. The absolute loss in performance after 2 weeks illuminated at 1300 suns equivalent and 125°C is 7 mV Voc and 0.2% efficiency, showing these devices to be relatively stable. The dark current increases with time and is analyzed with a two-diode model. A GaAs control cell degrades at the same rate, suggesting that the observed degradation mechanism is not related to the additional dislocations in the GaInAs devices.

Relationship between misfit-dislocation formation and initial threading-dislocation density in GaInN/GaN heterostructures

2015 ◽  
Vol 54 (11) ◽  
pp. 115501 ◽  
Author(s):  
Motoaki Iwaya ◽  
Taiji Yamamoto ◽  
Daisuke Iida ◽  
Yasunari Kondo ◽  
Mihoko Sowa ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Misfit Dislocation ◽  
Threading Dislocation ◽  
Threading Dislocation Density ◽  
Dislocation Formation

Enhanced reduction in threading dislocation density in Ge grown on porous silicon during annealing due to porous buffer reconstruction

2015 ◽  
Vol 213 (1) ◽  
pp. 96-101
Author(s):  
G. Calabrese ◽  
S. Baricordi ◽  
P. Bernardoni ◽  
D. De Salvador ◽  
M. Ferroni ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Threading Dislocation Density

Defect-Engineered Graded GexSi1-x Buffers on Si (001) with Extreme Low Threading Dislocation Density

1995 ◽  
Vol 378 ◽  
Author(s):  
G. Kissinger ◽  
T. Morgenstern ◽  
G. Morgenstern ◽  
H. B. Erzgräber ◽  
H. Richter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Threading Dislocation Density

AbstractStepwise equilibrated graded GexSii-x (x≤0.2) buffers with threading dislocation densities between 102 and 103 cm−2 on the whole area of 4 inch silicon wafers were grown and studied by transmission electron microscopy, defect etching, atomic force microscopy and photoluminescence spectroscopy.

A surfactant-mediated relaxed Si0.5Ge0.5 graded layer with a very low threading dislocation density and smooth surface

1999 ◽  
Vol 75 (11) ◽  
pp. 1586-1588 ◽  
Author(s):  
J. L. Liu ◽  
C. D. Moore ◽  
G. D. U’Ren ◽  
Y. H. Luo ◽  
Y. Lu ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Smooth Surface ◽  
Threading Dislocation ◽  
Threading Dislocation Density

C-V and DLTS Investigations of GaAs/InGaAs/GaAs Strained Quantum Well Structures

1993 ◽  
Vol 300 ◽  
Author(s):  
S. Subramanian ◽  
B. M. Arora ◽  
A. K. Srivastava ◽  
S. Banerjee ◽  
G. Fernandes
Keyword(s):  
Quantum Well ◽  
Band Offset ◽  
Full Width ◽  
Single Quantum ◽  
Single Quantum Well ◽  
Quantum Well Structures ◽  
Strained Quantum Well ◽  
Good Agreement

ABSTRACTIn this paper we report a modified Kroemer's analysis for the determination of the band offset (ΔEc) of single quantum well (SQW) structures from simple C-V measurements. The experimental carrier profile from an MOVPE grown pseudomorphic GaAs/InGaAs/GaAs strained SQW structure shows a sharp accumulation peak bounded by depletion regions on either side. The full width at half maximum of the accumulation peak is comparable to the width of the quantum well. The value of ΔEC obtained from C-V measurement is in good agreement with the values determined by simulation and photoluminescence measurements. DLTS measurements on our SQW samples do not show any peaks which is contrary to the published reports. We believe that it is necessary to carefully isolate the role of interface states, before assigning a DLTS peak to emission from the quantum well.

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