Novel Stm Probe Assisted Site-Control of Quantum Dots With Nanometer Precision

1999 ◽  
Vol 583 ◽  
Author(s):  
Hitoshi Nakamura ◽  
Shigeru Kohmoto ◽  
Tomonori Ishikawa ◽  
Kiyoshi Asakawa
Keyword(s):  
Quantum Dots ◽  
Gaas Surface ◽  
Control Technique ◽  
Formation Processes ◽  
Chamber System ◽  
Wetting Layer ◽  
Layer Formation ◽  
System A ◽  
Tungsten Tip ◽  
Site Control

AbstractWe propose a novel site-control technique for strained quantum dots (QDs) based on nano-lithography using an STM integrated into a UHV STM/MBE multi-chamber system. A nano-scale deposit was formed on a GaAs surface by applying voltage between the GaAs surface and the tungsten tip of the STM. Since the deposit acted as a nano-mask, the subsequent GaAs growth formed a nano-hole just above the deposit. Subsequent InAs supply produced a QD on the hole site, and no QD was observed in any undesirable regions. We also observed the QD formation processes involved in the technique, based on step-by-step STM observations of the QD formation process. The observation directly revealed an InAs wetting layer formation with 1-ML thickness on the GaAs terraces followed by the QD formation in the Stranski-Krastanow growth mode.

Wetting layer formation in superlattices with Ge quantum dots on Si(100)

2009 ◽  
Vol 40 (4-5) ◽  
pp. 782-784 ◽  
Author(s):  
A.I. Nikiforov ◽  
V.V. Ulyanov ◽  
V.A. Timofeev ◽  
O.P. Pchelyakov
Keyword(s):  
Quantum Dots ◽  
Wetting Layer ◽  
Layer Formation ◽  
Ge Quantum Dots

Photoluminescence Characteristics of InAs Quantum Dots Grown by STM/MBE Site-Control Technique

2001 ◽  
Vol 224 (2) ◽  
pp. 521-526 ◽  
Author(s):  
S. Nishikawa ◽  
S. Kohmoto ◽  
H. Nakamura ◽  
T. Ishikawa ◽  
K. Asakawa ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Control Technique ◽  
Inas Quantum Dots ◽  
Site Control

Interface engineered wetting-layer-free InAs quantum dots on GaAs(001)

2015 ◽  
Author(s):  
Manori V. Gunasekera ◽  
Dinghao Tang ◽  
Irene Rusakova ◽  
David J. Smith ◽  
Alexandre Freundlich
Keyword(s):  
Quantum Dots ◽  
Wetting Layer ◽  
Inas Quantum Dots

Wetting layer states in low density InAs/InGaAs quantum dots from sub-critical InAs coverages

2013 ◽  
Vol 46 (31) ◽  
pp. 315101 ◽  
Author(s):  
L Seravalli ◽  
G Trevisi ◽  
P Frigeri ◽  
F Rossi ◽  
E Buffagni ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Low Density ◽  
Wetting Layer

Stressor-Induced Site Control of Quantum Dots for Single-Photon Sources

2020 ◽  
pp. 53-90
Author(s):  
U. W. Pohl ◽  
A. Strittmatter ◽  
A. Schliwa ◽  
M. Lehmann ◽  
T. Niermann ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Single Photon ◽  
Photon Sources ◽  
Site Control

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.

Influence of GaAs capping on the optical properties of InGaAs/GaAs surface quantum dots with 1.5 μm emission

1998 ◽  
Vol 73 (19) ◽  
pp. 2742-2744 ◽  
Author(s):  
Hideaki Saito ◽  
Kenichi Nishi ◽  
Shigeo Sugou
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Gaas Surface
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