SELF-ORGANIZED QUANTUM DOTS

2002 ◽  
Vol 12 (01) ◽  
pp. 45-78 ◽  
Author(s):  
A. R. WOLL ◽  
P. RUGHEIMER ◽  
M. G. LAGALLY
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Self Assembly ◽  
The Self ◽  
Experimental Results ◽  
Size Distributions ◽  
Ongoing Research ◽  
Kinetics And Thermodynamics ◽  
Self Organized ◽  
Formation And Evolution

We review the concepts and principal experimental results pertaining to the self-assembly and self-ordering of quantum dots in semiconductor systems. We focus on the kinetics and thermodynamics of the formation and evolution of coherently strained 3D islands, and the effects of strain on nucleation, growth, and island shape. We also discuss ongoing research on methods to control the density, size, and size distributions of strained islands, both within a single strained layer and in quantum dot (QD) multilayers.

scholarly journals Tripeptide Self-Assembly into Bioactive Hydrogels: Effects of Terminus Modification on Biocatalysis

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 173
Author(s):  
Marina Kurbasic ◽  
Ana M. Garcia ◽  
Simone Viada ◽  
Silvia Marchesan
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Chemical Modifications ◽  
Ability To Work ◽  
Active Compounds ◽  
Future Design ◽  
Self Organized ◽  
The Future ◽  
Bio Material ◽  
Supramolecular Catalysts

Bioactive hydrogels based on the self-assembly of tripeptides have attracted great interest in recent years. In particular, the search is active for sequences that are able to mimic enzymes when they are self-organized in a nanostructured hydrogel, so as to provide a smart catalytic (bio)material whose activity can be switched on/off with assembly/disassembly. Within the diverse enzymes that have been targeted for mimicry, hydrolases find wide application in biomaterials, ranging from their use to convert prodrugs into active compounds to their ability to work in reverse and catalyze a plethora of reactions. We recently reported the minimalistic l-His–d-Phe–d-Phe for its ability to self-organize into thermoreversible and biocatalytic hydrogels for esterase mimicry. In this work, we analyze the effects of terminus modifications that mimic the inclusion of the tripeptide in a longer sequence. Therefore, three analogues, i.e., N-acetylated, C-amidated, or both, were synthesized, purified, characterized by several techniques, and probed for self-assembly, hydrogelation, and esterase-like biocatalysis. This work provides useful insights into how chemical modifications at the termini affect self-assembly into biocatalytic hydrogels, and these data may become useful for the future design of supramolecular catalysts for enhanced performance.

scholarly journals Nucleation of Ga droplets self-assembly on GaAs(111)A substrates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Artur Tuktamyshev ◽  
Alexey Fedorov ◽  
Sergio Bietti ◽  
Stefano Vichi ◽  
Riccardo Tambone ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Size Distribution ◽  
Self Assembly ◽  
Cluster Size ◽  
Droplet Size Distribution ◽  
Local Environment ◽  
The Self ◽  
Critical Cluster ◽  
Droplet Nucleation ◽  
High Degree

AbstractWe investigated the nucleation of Ga droplets on singular GaAs(111)A substrates in the view of their use as the seeds for the self-assembled droplet epitaxial quantum dots. A small critical cluster size of 1–2 atoms characterizes the droplet nucleation. Low values of the Hopkins-Skellam index (as low as 0.35) demonstrate a high degree of a spatial order of the droplet ensemble. Around $$350\,^{\circ }\hbox {C}$$ 350 ∘ C the droplet size distribution becomes bimodal. We attribute this observation to the interplay between the local environment and the limitation to the adatom surface diffusion introduced by the Ehrlich–Schwöbel barrier at the terrace edges.

Uniformity enhancement of the self-organized InAs quantum dots

1999 ◽  
Vol 197 (1-2) ◽  
pp. 372-375 ◽  
Author(s):  
Haijun Zhu ◽  
Zhiming Wang ◽  
Hui Wang ◽  
Liqiu Cui ◽  
Songlin Feng
Keyword(s):  
Quantum Dots ◽  
The Self ◽  
Inas Quantum Dots ◽  
Self Organized

Sub-wetting layer continuum states in the self-organized quantum dot samples

2002 ◽  
Vol 737 ◽  
Author(s):  
Král K. ◽  
Zdeněk P. ◽  
Z. Khás ◽  
M. Čerňanský
Keyword(s):  
Quantum Dots ◽  
Optical Spectra ◽  
The Self ◽  
Localized States ◽  
Wetting Layer ◽  
Self Organized ◽  
Growth Method ◽  
Extended States ◽  
Layer Region ◽  
The Individual

ABSTRACTIn polar semiconductor samples of the self-organized quantum dots, grown by the Stranski-Krastanow growth method, the lowest-energy extended states of the motion of the electronic excitations, are assumed to be the wetting-layer states. The coupling between these extended states and the electronic states localized in the individual quantum dots, may influence the optical spectra of such samples in the sub-wetting layer region of energy. This effect is studied assuming the Fröhlich's coupling between the electrons and the polar optical phonons. The contribution of this interaction to the appearance of the sub-wetting layer continuum in the optical spectra, and to the level broadening of the localized states, pointed out in some experiments, is estimated.

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