Structural atomic-scale analysis of GaAs/AlGaAs quantum wires and quantum dots grown by droplet epitaxy on a (311)A substrate

2011 ◽  
Vol 98 (19) ◽  
pp. 193112 ◽  
Author(s):  
J. G. Keizer ◽  
M. Jo ◽  
T. Mano ◽  
T. Noda ◽  
K. Sakoda ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Wires ◽  
Atomic Scale ◽  
Droplet Epitaxy ◽  
Scale Analysis

scholarly journals Atomic scale analysis of self assembled GaAs/AlGaAs quantum dots grown by droplet epitaxy

2010 ◽  
Vol 96 (6) ◽  
pp. 062101 ◽  
Author(s):  
J. G. Keizer ◽  
J. Bocquel ◽  
P. M. Koenraad ◽  
T. Mano ◽  
T. Noda ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Atomic Scale ◽  
Droplet Epitaxy ◽  
Scale Analysis ◽  
Self Assembled

Atomic-scale mapping of quantum dots formed by droplet epitaxy

2009 ◽  
Vol 4 (12) ◽  
pp. 835-838 ◽  
Author(s):  
Divine P. Kumah ◽  
Sergey Shusterman ◽  
Yossi Paltiel ◽  
Yizhak Yacoby ◽  
Roy Clarke
Keyword(s):  
Quantum Dots ◽  
Atomic Scale ◽  
Droplet Epitaxy

scholarly journals Atomic-Scale Characterization of Droplet Epitaxy Quantum Dots

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 85
Author(s):  
Raja S. R. Gajjela ◽  
Paul M. Koenraad
Keyword(s):  
Quantum Dots ◽  
Optoelectronic Devices ◽  
Atomic Scale ◽  
Droplet Epitaxy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Etch Pits ◽  
Cross Sectional ◽  
Scale Characterization

The fundamental understanding of quantum dot (QD) growth mechanism is essential to improve QD based optoelectronic devices. The size, shape, composition, and density of the QDs strongly influence the optoelectronic properties of the QDs. In this article, we present a detailed review on atomic-scale characterization of droplet epitaxy quantum dots by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography (APT). We will discuss both strain-free GaAs/AlGaAs QDs and strained InAs/InP QDs grown by droplet epitaxy. The effects of various growth conditions on morphology and composition are presented. The efficiency of methods such as flushing technique is shown by comparing with conventional droplet epitaxy QDs to further gain control over QD height. A detailed characterization of etch pits in both QD systems is provided by X-STM and APT. This review presents an overview of detailed structural and compositional analysis that have assisted in improving the fabrication of QD based optoelectronic devices grown by droplet epitaxy.

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.    

Annealing-Induced Structural Evolution of InAs Quantum Dots on InP (111)A Formed by Droplet Epitaxy

2021 ◽  
Author(s):  
Takaaki Mano ◽  
Akihiro Ohtake ◽  
Neul Ha ◽  
Takeshi Noda ◽  
Yoshiki Sakuma ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Structural Evolution ◽  
Droplet Epitaxy ◽  
Inas Quantum Dots
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