Impact of wetting-layer density of states on the carrier relaxation process in low indium content self-assembled (In,Ga)As/GaAs quantum dots

2013 ◽  
Vol 87 (12) ◽  
Author(s):  
M. Syperek ◽  
M. Baranowski ◽  
G. Sęk ◽  
J. Misiewicz ◽  
A. Löffler ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Relaxation Process ◽  
Density Of States ◽  
Indium Content ◽  
Wetting Layer ◽  
Carrier Relaxation ◽  
Layer Density ◽  
Self Assembled

Energy dependent carrier relaxation in self-assembled InAs/GaAs quantum dots

2008 ◽  
Vol 5 (9) ◽  
pp. 2709-2712
Author(s):  
H. S. Ling ◽  
C. P. Lee ◽  
S. Y. Wang ◽  
M. C. Lo
Keyword(s):  
Quantum Dots ◽  
Carrier Relaxation ◽  
Self Assembled ◽  
Energy Dependent

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

Carrier relaxation and quantum decoherence of excited states in self-assembled quantum dots

2001 ◽  
Vol 63 (24) ◽  
Author(s):  
H. Htoon ◽  
D. Kulik ◽  
O. Baklenov ◽  
A. L. Holmes ◽  
T. Takagahara ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Excited States ◽  
Quantum Decoherence ◽  
Carrier Relaxation ◽  
Self Assembled
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