Atomic Ordering in Self-assembled Epitaxial and Endotaxial Compound and Element Semiconductor Quantum Dot Structures: The First Review

AbstractAlthough the main international research thrust on self-assembled epitaxial semiconductor quantum dots is currently being directed towards random alloy quantum dots, the suggestion is made that atomically ordered quantum dots which are grown by either epitaxy or endotaxy may in addition to their larger quantum confinement potentials possess superior long term structural stability. Such atomically ordered quantum dots should, therefore, be superior to random alloy quantum dots as far as prospective device applications are concerned. The basis for this suggestion is simple thermodynamic considerations. These considerations seem to explain our transmission electron microscopical observations of epitaxially grown atomically ordered In(Sb,As), (In,Ga)Sb, (Cd,Zn)Se, (Cd,Mn,Zn)Se quantum dots and Pb(Se,Te) quantum dot predecessor islands. Atomic ordering in (In,Ga)P quantum dot structures, as recently observed by other authors, does not seem to contradict our thermodynamic considerations. Endotaxially grown atomically ordered (In,Si,As) and (Sn,Si) quantum dots in Si matrices are briefly discussed as an even more unconventional approach to nanostructures with applications in electronics, photonics, information storage, and sensing.

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InP Self Assembled Quantum Dot Lasers Grown on GaAs Substrates by Metalorganic Chemical Vapor Deposition

MRS Proceedings ◽

10.1557/proc-707-h11.6.1 ◽

2001 ◽

Vol 707 ◽

Author(s):

R. D. Dupuis ◽

J. H. Ryou ◽

R. D. Heller ◽

G. Walter ◽

D. A. Kellogg ◽

...

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Chemical Vapor ◽

Active Regions ◽

Threshold Current ◽

Double Quantum ◽

Force Microscopy ◽

Transmission Electron ◽

Self Assembled ◽

Inp Quantum Dots

ABSTRACTWe describe the operation of lasers having active regions composed of InP self-assembled quantum dots embedded in In0.5Al0.3Ga0.2P grown on GaAs (100) substrates by MOCVD. InP quantum dots grown on In0.5Al0.3Ga0.2P have a high density on the order of about 1-2x10 cm-2 with a dominant size of about 10-15 nm for 7.5 ML growth.[1] These In0.5Al0.3Ga0.2P/InP quantum dots have previously been characterized by atomic-force microscopy, high-resolution transmission electron microscopy, and photoluminescence.[2] We report here the 300K operation of optically pumped red-emitting quantum dots using both double quantum-dot active regions and quantum-dot coupled with InGaP quantum-well active regions. Optically and electrically pumped 300K lasers have been obtained using this active region design; these lasers show improved operation compared to the lasers having QD-based active regions with threshold current densities as low as Jth ∼ 0.5 KA/cm2.

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SELF-ASSEMBLED SEMICONDUCTOR QUANTUM DOTS: Fundamental Physics and Device Applications

Annual Review of Materials Research ◽

10.1146/annurev.matsci.34.082103.133534 ◽

2004 ◽

Vol 34 (1) ◽

pp. 181-218 ◽

Cited By ~ 90

Author(s):

M.S. Skolnick ◽

D.J. Mowbray

Keyword(s):

Quantum Dots ◽

Semiconductor Quantum Dots ◽

Fundamental Physics ◽

Device Applications ◽

Self Assembled

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Microstructures and Growth Characteristics of Self-Assembled InAs/GaAs Quantum Dots Investigated by Transmission Electron Microscopy

Advanced Materials Research - Advanced Materials and Processing ◽

10.4028/0-87849-463-4.1207 ◽

2007 ◽

pp. 1207-1210

Author(s):

Hyung Seok Kim ◽

Ju Hyung Suh ◽

Chan Gyung Park ◽

Sang Jun Lee ◽

Sam Kyu Noh ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Quantum Dots ◽

Growth Characteristics ◽

Transmission Electron ◽

Self Assembled

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Formation of ZnO/Zn0.5Cd0.5Se Alloy Quantum Dots in the Presence of High Oleylamine Contents

Nanomaterials ◽

10.3390/nano9070999 ◽

2019 ◽

Vol 9 (7) ◽

pp. 999

Author(s):

Yi-An Chen ◽

Kuo-Hsien Chou ◽

Yi-Yang Kuo ◽

Cheng-Ye Wu ◽

Po-Wen Hsiao ◽

...

Keyword(s):

Electron Microscopy ◽

Quantum Dots ◽

Particle Size ◽

X Ray Diffraction ◽

One Pot ◽

X Ray ◽

Transmission Electron ◽

Average Size ◽

Alloy Quantum Dots ◽

First Time

To the best of our knowledge, this report presents, for the first time, the schematic of the possible chemical reaction for a one-pot synthesis of Zn0.5Cd0.5Se alloy quantum dots (QDs) in the presence of low/high oleylamine (OLA) contents. For high OLA contents, high-resolution transmission electron microscopy (HRTEM) results showed that the average size of Zn0.5Cd0.5Se increases significantly from 4 to 9 nm with an increasing OLA content from 4 to 10 mL. First, [Zn(OAc)2]–OLA complex can be formed by a reaction between Zn(OAc)2 and OLA. Then, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) data confirmed that ZnO is formed by thermal decomposition of the [Zn(OAc)2]–OLA complex. The results indicated that ZnO grew on the Zn0.5Cd0.5Se surface, thus increasing the particle size. For low OLA contents, HRTEM images were used to estimate the average sizes of the Zn0.5Cd0.5Se alloy QDs, which were approximately 8, 6, and 4 nm with OLA loadings of 0, 2, and 4 mL, respectively. We found that Zn(OAc)2 and OLA could form a [Zn(OAc)2]–OLA complex, which inhibited the growth of the Zn0.5Cd0.5Se alloy QDs, due to the decreasing reaction between Zn(oleic acid)2 and Se2−, which led to a decrease in particle size.

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Heterogeneous structured MoSe2–MoO3 quantum dots with enhanced sodium/potassium storage

Journal of Materials Chemistry A ◽

10.1039/d0ta08674f ◽

2020 ◽

Vol 8 (44) ◽

pp. 23395-23403

Author(s):

Wen Liu ◽

Jujun Yuan ◽

Youchen Hao ◽

Hirbod Maleki Kheimeh Sari ◽

Jingjing Wang ◽

...

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Electrochemical Performance ◽

Heterogeneous Structure ◽

Sodium Potassium ◽

Self Assembled ◽

First Time

A quantum dot-assisted self-assembled MoSe2–MoO3 heterogeneous structure is investigated for sodium/potassium storage for the first time. The quantum dot-assisted self-assembled MoSe2–MoO3 anode possesses a better electrochemical performance.

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Microstructures and Growth Characteristics of Self-Assembled InAs/GaAs Quantum Dots Investigated by Transmission Electron Microscopy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.26-28.1207 ◽

2007 ◽

Vol 26-28 ◽

pp. 1207-1210

Author(s):

Hyung Seok Kim ◽

Ju Hyung Suh ◽

Chan Gyung Park ◽

Sang Jun Lee ◽

Sam Kyu Noh ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Quantum Dots ◽

Chemical Potential ◽

Early Stage ◽

Compressive Strain ◽

Potential Gradient ◽

Growth Direction ◽

Transmission Electron ◽

Self Assembled

The microstructure and strain characteristics of self-assembled InAs/GaAs quantum dots (QDs) were studied by using transmission electron microscopy. Compressive strain was induced to uncapped QDs from GaAs substrate and the misfit strain largely increased after the deposition of GaAs cap layer. Tensile strain outside QD was extended along the vertical growth direction; up to 15 nm above the wetting layer. Vertically nonaligned and aligned stacked QDs were grown by adjusting the thickness of GaAs spacer layers. The QDs with a lens-shaped morphology were formed in the early stage of growth, and their apex was flattened by the out-diffusion of In atoms upon GaAs capping. However, aligned QDs maintained their lens-shaped structure with round apex after capping. It is believed that their apex did not flatten because the chemical potential gradient of In was relatively low due to the adjacent InAs QD layers.

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