scholarly journals Density dependent composition of InAs quantum dots extracted from grazing incidence x-ray diffraction measurements

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Manjula Sharma ◽  
Milan K. Sanyal ◽  
Ian Farrer ◽  
David A. Ritchie ◽  
Arka B. Dey ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Density Dependent

Generalized Grazing Incidence-Angle X-Ray Diffraction Studies on InAs Quantum Dots on Si (100) Substrates

2000 ◽  
Vol 39 (Part 1, No. 7B) ◽  
pp. 4483-4485 ◽  
Author(s):  
Takeshi Uragami ◽  
Hiroshi Fujioka ◽  
Ichitaro Waki ◽  
Takaaki Mano ◽  
Kanta Ono ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Incidence Angle ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Grazing Incidence Angle

Emission and X ray diffraction in AlGaAs/ InGaAs Quantum wells with embedded InAs Quantum dots

2013 ◽  
Vol 1617 ◽  
pp. 43-48
Author(s):  
R. Cisneros Tamayo ◽  
I.J. Gerrero Moreno ◽  
A. Vivas Hernandez ◽  
J.L. Casas Espinola ◽  
L. Shcherbyna
Keyword(s):  
Quantum Dots ◽  
Quantum Wells ◽  
Thermal Annealing ◽  
Peak Position ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Prepared State ◽  
Temperature Dependences

ABSTRACTThe photoluminescence (PL), its temperature dependence and X-ray diffraction (XRD) have been studied in MBE grown GaAs/AlGaAs/InGaAs/AlGaAs /GaAs quantum wells (QWs) with InAs quantum dots embedded in the center of InGaAs layer in the freshly prepared states and after the thermal treatments during 2 hours at 640 or 710 °C. The structures contained two buffer (Al0.3Ga0.7As/In0.15Ga0.85As) and two capping (In0.15Ga0.85As / Al0.3Ga0.7As) layers. The temperature dependences of PL peak positions have been analyzed in the temperature range 10-500K with the aim to investigate the QD composition and its variation at thermal annealing. The experimental parameters of the temperature variation of PL peak position in the InAs QDs have been compared with the known one for the bulk InAs crystals and the QD composition variation due to Ga/Al/In inter diffusion at thermal treatments has been detected. XRD have been studied with the aim to estimate the capping/buffer layer compositions in the different QW layers in freshly prepared state and after the thermal annealing. The obtained emission and XRD data and their dependences on the thermal treatment have been analyzed and discussed.

InAs Quantum Dots Grown on an AlGaAsSb Strain-Relief Buffer

2000 ◽  
Vol 642 ◽  
Author(s):  
A.L. Gray ◽  
L. R. Dawson ◽  
Y. Lin ◽  
A. Stintz ◽  
Y.-C. Xin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cross Section ◽  
Gaas Substrate ◽  
Buffer Layers ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Strain Relief ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Transmission Electron

ABSTRACTAn In(Ga)As-based self-assembled quantum dot laser test structure grown on strain-relief Al0.5Ga0.5As1-ySby strain-relief buffer layers (0≤y ≤ 0.24) on a GaAs substrate is investigated in an effort to increase dot size and therefore extend the emission wavelength over conventional InAs quantum dots on GaAs platforms. Cross-section transmission electron microscopy, and high-resolution x-ray diffraction are used to monitor the dislocation filtering process and morphology in the buffer layers. Results show that the buffer layers act as an efficient dislocation filter by drastically reducing threading dislocations, thus providing a relaxed, low dislocation, compositionally modulated Al0.5Ga0.5Sb0.24As0.76 substrate for large (500Å height x 300Å width) defect -free InAs quantum dots. Photoluminescence shows a ground-state emission of the InAs quantum dots at 1.45 μm.

X-Ray diffraction analysis of multilayer InAs-GaAs heterostructures with InAs quantum dots

1999 ◽  
Vol 33 (11) ◽  
pp. 1229-1237 ◽  
Author(s):  
N. N. Faleev ◽  
A. Yu. Egorov ◽  
A. E. Zhukov ◽  
A. R. Kovsh ◽  
S. S. Mikhrin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
Inas Quantum Dots ◽  
X Ray

Optical And Structural properties of Vertical Aligned Self-Assembled InAs Quantum Dots Multilayers

2001 ◽  
Vol 676 ◽  
Author(s):  
J. C. González ◽  
M. I. N. da Silva ◽  
W. N. Rodrigues ◽  
F. M. Matinaga ◽  
R. Magalhaes-Paniago ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Structural Properties ◽  
Molecular Beam ◽  
X Ray Diffraction ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Self Assembled

ABSTRACTIn this work, we report optical and structural properties of vertical aligned self-assembled InAs quantum dots multilayers. The InAs quantum dots samples were grown by Molecular Beam Epitaxy. Employing Atomic Force Microscopy, Transmission Electron Microscopy, and Gracing Incident X-ray Diffraction we have studied the structural properties of samples with different number of periods of the multiplayer structure, as well as different InAs coverage. The optical properties were studied using Photoluminescence spectroscopy.

Direct observation of strain in InAs quantum dots and cap layer during molecular beam epitaxial growth using in situ X-ray diffraction

2015 ◽  
Vol 118 (18) ◽  
pp. 185303 ◽  
Author(s):  
Kenichi Shimomura ◽  
Hidetoshi Suzuki ◽  
Takuo Sasaki ◽  
Masamitu Takahasi ◽  
Yoshio Ohshita ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Epitaxial Growth ◽  
Direct Observation ◽  
Molecular Beam ◽  
X Ray Diffraction ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Molecular Beam Epitaxial ◽  
Molecular Beam Epitaxial Growth

Double crystal X-ray diffraction study of MBE self-organized InAs quantum dots

1998 ◽  
Vol 41 (2) ◽  
pp. 172-176 ◽  
Author(s):  
Yutian Wang ◽  
Yan Zhuang ◽  
Wenquan Ma ◽  
Wei Wang ◽  
Xiaoping Yang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Diffraction Study ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Self Organized

Temperature Dependent Characterization of Imbedded InAs Quantum Dots in GaAs Superlattice Solar Cell Structures by High Resolution X-ray Diffraction

2012 ◽  
Vol 1432 ◽  
Author(s):  
Josephine J. Sheng ◽  
David. C. Chapman ◽  
David M. Wilt ◽  
Stephen J. Polly ◽  
Christopher G. Bailey ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Solar Cell ◽  
High Resolution ◽  
Nanostructured Materials ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Cell Structures

ABSTRACTThe insertion of nanostructured materials (such as quantum wells, wires, and dots) into the intrinsic region of p-i-n solar cells introduces an intermediate band within the bandgap of the host material. It has been shown that the sub-bandgap conversion provided by the nanostructured materials, enhances the short circuit current as well as the overall efficiency of InAs quantum dots (QD) imbedded in GaAs superlattice (SL) solar cells [1]. As a contender for space applications, it is necessary to subject these solar cell structures to temperatures encountered in the Low Earth Orbit (LEO), probing for any material degradation. Herein, we focus on temperature dependent characterization using high resolution X-ray diffraction (HRXRD) of InAs QD enhanced GaAs solar cell structures with varying growth parameters. The structures characterized can be classified into three groups: (1) GaP strain compensation coverage, (2) GaAs barrier coverage, and (3) InAs coverage for QD formation. HRXRD rocking curves of each structure focusing around the GaAs peak are analyzed at a range of temperatures up to 200˚C. Although no noticeable shifts in the SL peaks are detected, interfacial diffusion decreased the resolution of fringes produced by reflections at the SL interfaces in test structures with varying InAs QD coverage. Unbalanced strain in the same structures shows a distortion in the GaAs peaks.

HR XRD and Emission of InxGa1-xAs/GaAs quantum wells with embedded InAs quantum dots at the variation of InxGa1-xAs composition

2013 ◽  
Vol 1617 ◽  
pp. 13-18
Author(s):  
Leonardo G. Vega Macotela ◽  
Ricardo Cisneros Tamayo ◽  
Georgiy Polupan
Keyword(s):  
Quantum Dots ◽  
Quantum Wells ◽  
Technological Changes ◽  
Structural Effects ◽  
X Ray Diffraction ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Versus Parameter ◽  
Physical Reasons ◽  
Elastic Strains

ABSTRACTThe high resolution X ray diffraction (HR-XRD) diagrams have been studied in the GaAs /InxGa1-xAs /In0.15Ga0.85As/GaAs quantum wells with embedded InAs quantum dots (QDs) in dependence on the composition of the capping InxGa1-xAs layers. The parameter x in capping InxGa1-xAs layers varied from the range 0.10-0.25. These technological changes have been accompanied by the variation non-monotonously of InAs QD emission. Numerical simulation of HR-XRD results has shown that the level of elastic strains and the composition of quantum layers vary none monotonously in studied QD structures. Simultaneously it was revealed that the process of Ga/In inter diffusion at the InxGa1-xAs/InAs QD interface are characterized by the dependence non monotonous versus parameter x in capping InxGa1-xAs layers. The physical reasons of the mentioned optical and structural effects in studied structures have been discussed.

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