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

Fabrication of Self-Assembled GaAs/AlGaAs Quantum Dots by Low-Temperature Droplet Epitaxy

1998 ◽  
Vol 37 (Part 1, No. 12B) ◽  
pp. 7158-7160 ◽  
Author(s):  
Chae-Deok Lee ◽  
Chanro Park ◽  
Hwack Joo Lee ◽  
Kyu-Seok Lee ◽  
Seong-Ju Park ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Low Temperature ◽  
Droplet Epitaxy ◽  
Self Assembled

Self-assembled Quantum Dots: From Stranski–Krastanov to Droplet Epitaxy

2011 ◽  
pp. 127-200 ◽  
Author(s):  
Yu. G. Galitsyn ◽  
A. A. Lyamkina ◽  
S. P. Moshchenko ◽  
T. S. Shamirzaev ◽  
K. S. Zhuravlev ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Droplet Epitaxy ◽  
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

Modified droplet epitaxy GaAs/AlGaAs quantum dots grown on a variable thickness wetting layer

2003 ◽  
Vol 253 (1-4) ◽  
pp. 71-76 ◽  
Author(s):  
S. Sanguinetti ◽  
K. Watanabe ◽  
T. Tateno ◽  
M. Gurioli ◽  
P. Werner ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Variable Thickness ◽  
Droplet Epitaxy ◽  
Wetting Layer

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.

EFFECTS OF ANTIMONY FLUX ON MORPHOLOGY AND PHOTOLUMINESCENCE SPECTRA OF GaSb QUANTUM DOTS FORMED ON GaAs BY DROPLET EPITAXY

2010 ◽  
Vol 19 (04) ◽  
pp. 819-826 ◽  
Author(s):  
T. KAWAZU ◽  
T. NODA ◽  
T. MANO ◽  
M. JO ◽  
H. SAKAKI
Keyword(s):  
Quantum Dots ◽  
Microscope Study ◽  
Molecular Beam ◽  
Broad Peak ◽  
Droplet Epitaxy ◽  
Wetting Layer ◽  
Photoluminescence Spectra ◽  
Coalescence Process ◽  
Strong Luminescence

We investigated effects of the antimony flux on GaSb quantum dots (QDs) formed by droplet epitaxy. Ga droplets were first formed on GaAs and exposed to Sb4 molecular beam at 200 °C, where the flux PSb of Sb beam was varied from 2.4 to 12.8 × 10-7 Torr. The samples were then annealed for 2 minutes under the Sb flux. An atomic microscope study showed that the diameter of GaSb QDs increases and the density decreases, as the Sb flux PSb is increased. This indicates that the coalescence process of GaSb QDs occurs and is accelerated by the increase of the Sb flux. In a photoluminescence (PL) study, we observed a broad peak of GaSb QDs in all samples, while a strong luminescence of a wetting layer (WL)-like structure was found only in the samples prepared with the high Sb flux. This suggests that the PL of WL is controllable by adjusting the flux PSb of Sb beam.

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