scholarly journals Phase Separation Inside the CdTe−CdSe Type II Quantum Dots Revealed by Synchrotron X-ray Diffraction and Scattering

2008 ◽  
Vol 112 (26) ◽  
pp. 9617-9622 ◽  
Author(s):  
Hwo-Shuenn Sheu ◽  
U-Ser Jeng ◽  
Wei-Ju Shih ◽  
Ying-Huang Lai ◽  
Chiu-Hun Su ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Phase Separation ◽  
Type Ii ◽  
X Ray Diffraction ◽  
X Ray

Cation distributions and possible phase separation inTl2Ba2CuO6+δfrom synchrotron powder x-ray diffraction

1995 ◽  
Vol 51 (18) ◽  
pp. 12747-12753 ◽  
Author(s):  
M. A. G. Aranda ◽  
D. C. Sinclair ◽  
J. P. Attfield ◽  
A. P. Mackenzie
Keyword(s):  
Phase Separation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cation Distributions

Detailed X-ray diffraction studies on optically pumped mid-infrared InAs/Ga(In)Sb/AlSb type-II lasers

2003 ◽  
Vol 257 (1-2) ◽  
pp. 42-50 ◽  
Author(s):  
G. Hoffmann ◽  
H.J. Schimper ◽  
C. Schwender ◽  
N. Herhammer ◽  
G.F. West ◽  
...  
Keyword(s):  
Type Ii ◽  
X Ray Diffraction ◽  
Optically Pumped ◽  
Mid Infrared ◽  
X Ray

scholarly journals Observation of ordered organic capping ligands on semiconducting quantum dots via powder X-ray diffraction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jason J. Calvin ◽  
Tierni M. Kaufman ◽  
Adam B. Sedlak ◽  
Michelle F. Crook ◽  
A. Paul Alivisatos
Keyword(s):  
Quantum Dots ◽  
Colloidal System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ligand Shell ◽  
Scattering Factor ◽  
Organic Capping ◽  
Capping Ligands ◽  
Key Techniques ◽  
Inorganic Structure

AbstractPowder X-ray diffraction is one of the key techniques used to characterize the inorganic structure of colloidal nanocrystals. The comparatively low scattering factor of nuclei of the organic capping ligands and their propensity to be disordered has led investigators to typically consider them effectively invisible to this technique. In this report, we demonstrate that a commonly observed powder X-ray diffraction peak around $$q=1.4{\AA}^{-1}$$ q = 1.4 Å − 1 observed in many small, colloidal quantum dots can be assigned to well-ordered aliphatic ligands bound to and capping the nanocrystals. This conclusion differs from a variety of explanations ascribed by previous sources, the majority of which propose an excess of organic material. Additionally, we demonstrate that the observed ligand peak is a sensitive probe of ligand shell ordering. Changes as a function of ligand length, geometry, and temperature can all be readily observed by X-ray diffraction and manipulated to achieve desired outcomes for the final colloidal system.

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.

Optical properties and energy transfer processes in Tb3+-doped ZnSe quantum dots

2021 ◽  
Author(s):  
Nguyen Ca ◽  
N. D Vinh ◽  
Phan Van Do ◽  
N. T. Hien ◽  
Xuan Hoa Vu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Chemical Method ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Transfer Processes ◽  
Transmission Electron ◽  
Wet Chemical

Tb3+-doped ZnSe quantum dots (QDs) with Tb content in the range of 0.5 - 7% were successfully synthesized by a wet chemical method. X-ray diffraction (XRD) and transmission electron microscopy...

Microstructure characteristics of non-monodisperse quantum dots: on the potential of transmission electron microscopy combined with X-ray diffraction

CrystEngComm ◽  
2020 ◽  
Vol 22 (21) ◽  
pp. 3644-3655
Author(s):  
Stefan Neumann ◽  
Christina Menter ◽  
Ahmed Salaheldin Mahmoud ◽  
Doris Segets ◽  
David Rafaja
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Cdse Quantum Dots ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructure Characteristics ◽  
Scale Bridging ◽  
Transmission Electron ◽  
Hot Injection

Capability of TEM and XRD to reveal scale-bridging information about the microstructure of non-monodisperse quantum dots is illustrated on the CdSe quantum dots synthesized using an automated hot-injection method.

scholarly journals The phase diagram of a mixed halide (Br, I) hybrid perovskite obtained by synchrotron X-ray diffraction

RSC Advances ◽  
2019 ◽  
Vol 9 (20) ◽  
pp. 11151-11159 ◽  
Author(s):  
Frederike Lehmann ◽  
Alexandra Franz ◽  
Daniel M. Többens ◽  
Sergej Levcenco ◽  
Thomas Unold ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Solid Solution ◽  
Phase Separation ◽  
Structural Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Perovskite

The phase diagram elucidates structural changes and phase separation effects, induced by halide substitution in hybrid perovskite MAPb(I,Br)3 solid solution.

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