Mechanism for controlling the exciton fine structure in quantum dots using electric fields: Manipulation of exciton orientation and exchange splitting at the atomic scale

2013 ◽  
Vol 88 (16) ◽  
Author(s):  
Garnett W. Bryant ◽  
Natalia Malkova ◽  
James Sims
Keyword(s):  
Quantum Dots ◽  
Fine Structure ◽  
Electric Fields ◽  
Atomic Scale ◽  
Exchange Splitting

Influence of lateral electric fields on multiexcitonic transitions and fine structure of single quantum dots

2007 ◽  
Vol 91 (5) ◽  
pp. 051904 ◽  
Author(s):  
M. M. Vogel ◽  
S. M. Ulrich ◽  
R. Hafenbrak ◽  
P. Michler ◽  
L. Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Fine Structure ◽  
Electric Fields ◽  
Single Quantum ◽  
Single Quantum Dots

Atomic-scale visualization of metallic lead leak related fine structure in CsPbBr3 quantum dots

Nanoscale ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 124-130
Author(s):  
Xinyu Liu ◽  
Jianlin Wang ◽  
Chaojie Ma ◽  
Xudan Huang ◽  
Kaihui Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electronic Structure ◽  
Fine Structure ◽  
Atomic Scale ◽  
Atomic Resolution ◽  
Metallic Lead ◽  
Cspbbr3 Quantum Dots ◽  
Atomic And Electronic Structure

The fine atomic and electronic structure of Pb-leaked CsPbBr3 quantum dots have been revealed using atomic-resolution STEM.

Off-axis electron holography applied to the study of interfaces

1992 ◽  
Vol 50 (1) ◽  
pp. 244-245
Author(s):  
J.K. Weiss ◽  
M. Gajdardziska-Josifovska ◽  
M. R. McCartney ◽  
David J. Smith
Keyword(s):  
Electric Fields ◽  
Resolution Enhancement ◽  
Interfacial Structure ◽  
Atomic Scale ◽  
Bulk Property ◽  
Electron Holography ◽  
Specimen Thickness ◽  
Composition And Structure ◽  
Chemical Segregation ◽  
Diffraction Effects

Interfacial structure is a controlling parameter in the behavior of many materials. Electron microscopy methods are widely used for characterizing such features as interface abruptness and chemical segregation at interfaces. The problem for high resolution microscopy is to establish optimum imaging conditions for extracting this information. We have found that off-axis electron holography can provide useful information for the study of interfaces that is not easily obtained by other techniques.Electron holography permits the recovery of both the amplitude and the phase of the image wave. Recent studies have applied the information obtained from electron holograms to characterizing magnetic and electric fields in materials and also to atomic-scale resolution enhancement. The phase of an electron wave passing through a specimen is shifted by an amount which is proportional to the product of the specimen thickness and the projected electrostatic potential (ignoring magnetic fields and diffraction effects). If atomic-scale variations are ignored, the potential in the specimen is described by the mean inner potential, a bulk property sensitive to both composition and structure. For the study of interfaces, the specimen thickness is assumed to be approximately constant across the interface, so that the phase of the image wave will give a picture of mean inner potential across the interface.

High-Temperature Synthesis of CdSe-Based Core/Shell, Core/Shell/Shell, and Core/Graded-Shell Nanoplatelets for Stable and Efficient Narrowband Emitters

2019 ◽  
Author(s):  
Aurelio A. Rossinelli ◽  
Henar Rojo ◽  
Aniket S. Mule ◽  
Marianne Aellen ◽  
Ario Cocina ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Temperature ◽  
Equilibrium Shape ◽  
Size Variation ◽  
Crystal Defects ◽  
Atomic Scale ◽  
Quantum Yields ◽  
Core Shell ◽  
Compositional Gradient ◽  
High Quality

<div>Colloidal semiconductor nanoplatelets exhibit exceptionally narrow photoluminescence spectra. This occurs because samples can be synthesized in which all nanoplatelets share the same atomic-scale thickness. As this dimension sets the emission wavelength, inhomogeneous linewidth broadening due to size variation, which is always present in samples of quasi-spherical nanocrystals (quantum dots), is essentially eliminated. Nanoplatelets thus offer improved, spectrally pure emitters for various applications. Unfortunately, due to their non-equilibrium shape, nanoplatelets also suffer from low photo-, chemical, and thermal stability, which limits their use. Moreover, their poor stability hampers the development of efficient synthesis protocols for adding high-quality protective inorganic shells, which are well known to improve the performance of quantum dots. <br></div><div>Herein, we report a general synthesis approach to highly emissive and stable core/shell nanoplatelets with various shell compositions, including CdSe/ZnS, CdSe/CdS/ZnS, CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S, and CdSe/ZnSe. Motivated by previous work on quantum dots, we find that slow, high-temperature growth of shells containing a compositional gradient reduces strain-induced crystal defects and minimizes the emission linewidth while maintaining good surface passivation and nanocrystal uniformity. Indeed, our best core/shell nanoplatelets (CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S) show photoluminescence quantum yields of 90% with linewidths as low as 56 meV (19.5 nm at 655 nm). To confirm the high quality of our different core/shell nanoplatelets for a specific application, we demonstrate their use as gain media in low-threshold ring lasers. More generally, the ability of our synthesis protocol to engineer high-quality shells can help further improve nanoplatelets for optoelectronic devices.</div>

Carbon Nanotubes, Quantum Dots and Dendrimers as Potential Nanodevices for Nanotechnology Drug Delivery Systems

2013 ◽  
Vol 6 (3) ◽  
pp. 2113-2124
Author(s):  
Prashant Malik ◽  
Neha Gulati ◽  
Raj Kaur Malik ◽  
Upendra Nagaich
Keyword(s):  
Carbon Nanotubes ◽  
Drug Delivery ◽  
Quantum Dots ◽  
Self Assembly ◽  
Drug Delivery Systems ◽  
Delivery Systems ◽  
Atomic Scale ◽  
Sustained Drug Delivery ◽  
Pharmaceutical Nanotechnology ◽  
Conventional Device

Nanotechnology deal with the particle size in nanometers. Nanotechnology is ranging from extensions of conventional device physics to completely new approaches based upon molecular self assembly, from developing new materials with dimensions on the nanoscale to direct control of matter on the atomic scale. In nanotechnology mainly three types of nanodevices are described: carbon nanotubes, quantum dots and dendrimers. It is a recent technique used as small size particles to treat many diseases like cancer, gene therapy and used as diagnostics. Nanotechnology used to formulate targeted, controlled and sustained drug delivery systems. Pharmaceutical nanotechnology embraces applications of nanoscience to pharmacy as nanomaterials and as devices like drug delivery, diagnostic, imaging and biosensor materials. Pharmaceutical nanotechnology has provided more fine tuned diagnosis and focused treatment of disease at a molecular level.    

Exciton fine structure splitting of single InGaAs self-assembled quantum dots

2004 ◽  
Vol 21 (2-4) ◽  
pp. 175-179 ◽  
Author(s):  
A Högele ◽  
B Alèn ◽  
F Bickel ◽  
R.J Warburton ◽  
P.M Petroff ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Fine Structure ◽  
Fine Structure Splitting ◽  
Structure Splitting ◽  
Self Assembled

scholarly journals Atomic scale investigations on CdxZn1−xSe quantum dots: Correlation between the composition and emission properties

2014 ◽  
Vol 105 (5) ◽  
pp. 053103 ◽  
Author(s):  
H. Benallali ◽  
T. Cremel ◽  
K. Hoummada ◽  
D. Mangelinck ◽  
R. André ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Atomic Scale ◽  
Emission Properties
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