Influence of the wetting-layer growth kinetics on the size and shape of Ge self-assembled quantum dots on Si(001)

2001 ◽  
Vol 79 (2) ◽  
pp. 263-265 ◽  
Author(s):  
H. J. Kim ◽  
Y. H. Xie
Keyword(s):  
Quantum Dots ◽  
Growth Kinetics ◽  
Layer Growth ◽  
Wetting Layer ◽  
Size And Shape ◽  
Self Assembled

The Effect of Upper Barrier Layer Growth on Self-Assembled CdSe Quantum Dots

2002 ◽  
Vol 229 (1) ◽  
pp. 457-461
Author(s):  
Y. Murase ◽  
K. Maehashi ◽  
T. Hanada ◽  
Y. Hirotsu ◽  
H. Nakashima
Keyword(s):  
Quantum Dots ◽  
Barrier Layer ◽  
Layer Growth ◽  
Cdse Quantum Dots ◽  
Self Assembled

Growth and Overgrowth of Ge/Si Quantum Dots: An Observation by Atomic Resolution HAADF-STEM Imaging

2004 ◽  
Vol 832 ◽  
Author(s):  
Dan Zhi ◽  
Paul A. Midgley ◽  
Rafal E. Dunin-Borkowski ◽  
Bruce A. Joyce ◽  
Don W. Pashley ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Direct Analysis ◽  
Lateral Spreading ◽  
Dark Field ◽  
Atomic Scale ◽  
Wetting Layer ◽  
Compositional Evolution ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Self Assembled

ABSTRACTThe formation of self-assembled quantum dots (QD) is of increasing interest for applications in optical, nanoelectronic, biological and quantum computing systems. From the perspective of fabrication technology, there are great advantages if the whole device can be made using a single Si substrate. Furthermore, GeSi is a model semiconductor system for fundamental studies of growth and material properties. In practice, as the MBE growth of heterostructures is inherently a non-equilibrium process, the formation of self-assembled nanostructures is both complex and sensitive to growth and overgrowth conditions. The morphology, structure and composition of QDs can all change during growth. It is therefore crucial to understand their structures at different stages of growth at the atomic scale. Here, the characterization of QD growth using high-resolution high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) imaging is presented. Both the formation of uncapped QDs and the effect of the encapsulation are investigated, and the morphological and compositional evolution of the QDs and wetting layers are observed directly at the atomic scale for the first time. During encapsulation, the Ge content in the centres of the QD remains unchanged, despite significant intermixing, lateral spreading and a laterally inhomogeneous Ge distribution inside the Ge QD. The initial non-uniform wetting layer for the uncapped Ge QD becomes uniform after encapsulation, and a 3-monolayer-thick core with ∼ 60% Ge content is formed in the 2 nm-thick wetting layer with an average Ge content of ∼ 30%. The results were obtained by direct analysis of the Z-contrast STEM imaging without involving complex image simulations.

scholarly journals Influence of wetting-layer wave functions on phonon-mediated carrier capture into self-assembled quantum dots

2006 ◽  
Vol 74 (19) ◽  
Author(s):  
Troels Markussen ◽  
Philip Kristensen ◽  
Bjarne Tromborg ◽  
Tommy Winther Berg ◽  
Jesper Mørk
Keyword(s):  
Quantum Dots ◽  
Wave Functions ◽  
Wetting Layer ◽  
Carrier Capture ◽  
Self Assembled

Growth Kinetics and Formation of Uniform Self-Assembled InAs/GaAs Quantum Dots at

2007 ◽  
Vol 124-126 ◽  
pp. 539-542
Author(s):  
Eui Tae Kim ◽  
Anupam Madhukar
Keyword(s):  
Growth Rate ◽  
Quantum Dots ◽  
Growth Kinetics ◽  
Slow Growth ◽  
Fast Growth ◽  
Slow Growth Rate ◽  
Self Assembled ◽  
Kinetics Of ◽  
Fast Growth Rate ◽  
2D To 3D

We discuss the growth kinetics of InAs/GaAs self-assembled quantum dots (QDs) using two different InAs deposition rates, relatively fast growth rate of 0.22 ML/sec and slow growth rate of 0.054 ML/sec. With increasing InAs deposition amount to 3.0 ML, the QD density was almost constant after 2D to 3D island transition at the slow deposition rate while the QD density kept increasing and the QD size distribution was relatively broad at the fast growth rate. After the 2D to 3D transition, at the slow growth rate, further deposited In adatoms seemed to incorporate primarily into already formed islands, and thus contribute to equalize island size. The photoluminescence (PL) full-width at half maximum (FWHM) of 2.5 ML InAs QDs at 0.054 ML/sec was 23 meV at 78K. The PL characteristics of InAs/GaAs QDs were degraded significantly after thermal annealing at 550 oC for 3 hours.

scholarly journals Kondo-excitons and Auger processes in self-assembled quantum dots

2002 ◽  
Vol 737 ◽  
Author(s):  
A. O. Govorov ◽  
K. Karrai ◽  
R. J. Warburton ◽  
A. V. Kalameitsev
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Electron Spin ◽  
Electron Gas ◽  
Kondo Temperature ◽  
Two Dimensional ◽  
Wetting Layer ◽  
Voltage Dependent ◽  
Self Assembled ◽  
The Continuum

ABSTRACTWe describe theoretically novel excitons in self-assembled quantum dots interacting with a two-dimensional (2D) electron gas in the wetting layer. In the presence of the Fermi sea, the optical lines become strongly voltage-dependent. If the electron spin is nonzero, the width of optical lines is given by kBTK, where TK is Kondo temperature. If the spin is zero, the exciton couples with the continuum due to Auger-like processes. This leads to anticrossings in a magnetic field. Such states can be called Kondo-Anderson excitons. Some of the described phenomena are observed in recent experiments.

Self-assembled GaAs quantum dots coupled with GaAs wetting layer grown on GaAs (311)A by droplet epitaxy

2010 ◽  
Vol 8 (2) ◽  
pp. 257-259 ◽  
Author(s):  
Takaaki Mano ◽  
Takeshi Noda ◽  
Takashi Kuroda ◽  
Stefano Sanguinetti ◽  
Kazuaki Sakoda
Keyword(s):  
Quantum Dots ◽  
Droplet Epitaxy ◽  
Wetting Layer ◽  
Self Assembled
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