Mechanically Biased Self-Assembly of Quantum Dots by Nanoindentation

2006 ◽  
Vol 921 ◽  
Author(s):  
Curtis R. Taylor ◽  
Ajay Malshe ◽  
Eric Stach ◽  
Euclydes Marega ◽  
Gregory Salamo
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Surface Strain ◽  
Ex Situ ◽  
Atomic Step ◽  
Inas Quantum Dots ◽  
Force Microscopy ◽  
Patterned Growth ◽  
Atomic Force ◽  
Cube Corner

AbstractNanoindentations were created in the GaAs(100) surface to act as strain centers to bias the nucleation of self-assembled InAs quantum dots providing for patterned growth. Indents were generated using loads below 450 μN with a sharp cube corner indenter. Growth of InAs quantum dots on indent patterns is performed using molecular beam epitaxy (MBE). The effect of indent spacing and size on the patterned growth is investigated. The structural analysis of the quantum dots including spatial ordering, size, and shape are characterized by ex-situ atomic force microscopy (AFM). Results reveal that the indent patterns clearly bias nucleation with dot structures selectively growing on top of each indent. It is speculated that the biased nucleation is due to a combination of favorable surface strain and multi-atomic step formation at the indent sites, which leads to increased adatom diffusion on the patterned area.

Nanoindentation Assisted Self-Assembly of Quantum Dots

2006 ◽  
Author(s):  
Curtis Taylor ◽  
Eric Stach ◽  
Gregory Salamo ◽  
Ajay Malshe
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Surface Strain ◽  
Ex Situ ◽  
Atomic Step ◽  
Uniform Size ◽  
Force Microscopy ◽  
Atomic Force ◽  
And Performance ◽  
Spatial Positioning

The ability to pattern quantum dots with high spatial positioning and uniform size is critical for the realization of future electronic devices with novel properties and performance that surpass present technology. This work discusses the exploration of an innovative nanopatterning technique to direct the self-assembly of nanostructures. The technique focuses on perturbing surface strain energy by nanoindentation in order to mechanically bias quantum dot nucleation. Growth of InAs quantum dots on nanoindent templates is performed using molecular beam epitaxy (MBE). The effect of indent spacing and size on the patterned growth is investigated. The structural analysis of the quantum dots including spatial ordering, size, and shape are characterized by ex-situ atomic force microscopy (AFM). Results reveal that the indent patterns clearly bias nucleation with dot structures selectively growing on top of each indent. It is speculated that the biased nucleation is due to a combination of favorable surface strain attributed to subsurface dislocation strain fields and/or multi-atomic step formation at the indent sites, which leads to increased adatom diffusion on the patterned area.

Dynamics of InAs Quantum Dots Formation on AlAs and GaAs

2000 ◽  
Vol 648 ◽  
Author(s):  
M. Yakimov ◽  
V. Tokranov ◽  
S. Oktyabrsky
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Single Layer ◽  
High Energy ◽  
Ex Situ ◽  
Inas Quantum Dots ◽  
Force Microscopy ◽  
Atomic Force ◽  
Kinetics Of

AbstractWe have studied the formation of InAs quantum dots (QDs) grown by molecular beam epitaxy on top of GaAs and 2 ML-thick AlAs layers in the temperature range from 350 to 500°C. In-situ reflection high energy electron diffraction (RHEED) patterns were recorded in real time during the growth and analyzed to characterize the 2D-to-3D transition on the surface, including QD formation, and ripening process. The kinetics of QD formation was studied using the InAs growth rates ranging from 0.01 to 1 ML/s and different ratios of As2/In fluxes. RHEED patterns and ex-situ atomic force microscopy images were analyzed to reveal the development of sizes and shapes of the single-layer and stacked QD ensembles. The critical InAs coverage for QD formation was shown to be consistently higher for dots grown on the AlAs overlayer than for those grown on GaAs surface. Self-assembly of multilayer QD stacks revealed the reduction of the critical thickness for dots formed in the upper layers.

Guided Self Assembly of InAs Quantum Dots on a Cleaved Facet

2006 ◽  
Vol 959 ◽  
Author(s):  
Emanuele Uccelli ◽  
Dieter Schuh ◽  
Jochen Bauer ◽  
Max Bichler ◽  
Jonathan J. Finley ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Atomic Force Microscopy ◽  
Growth Mechanism ◽  
Self Assembly ◽  
Semiconductor Quantum Dots ◽  
Preferential Growth ◽  
Inas Quantum Dots ◽  
Force Microscopy ◽  
Atomic Force ◽  
Long Range Ordering

ABSTRACTThe long range ordering of epitaxial semiconductor quantum dots (QDs) has been obtained by combing self assembly with the cleaved edge overgrowth technique. The introduction of nanometer thick AlAs stripes on a (110) oriented GaAs surface avoids the misfit dislocation growth mechanism of InAs on GaAs (110) and drives the formation of array of QDs. Atomic Force Microscopy (AFM) investigations highlight that InAs QDs only nucleate in chain like structure on Al-rich regions. Here, we present experimental results that demonstrate the ability to create ordered QDs lattices and discuss the conditions under which preferential growth of QDs on the AlAs stripes occurs.

Growth and characterization of InAs quantum dots on GaAs (100) emitting at 1.31μm.

2003 ◽  
Vol 794 ◽  
Author(s):  
V. Celibert ◽  
B. Salem ◽  
G. Guillot ◽  
C. Bru-Chevallier ◽  
L. Grenouillet ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Excitation Power ◽  
Good Growth ◽  
Excitation Power Density ◽  
Inas Quantum Dots ◽  
Force Microscopy ◽  
Self Organized ◽  
Gas Source ◽  
Atomic Force ◽  
Layer Deposition

ABSTRACTSelf-organized InAs quantum dots (QDs) were grown in the Stranski-Krastanov regime, by gas-source molecular beam epitaxy (GSMBE), on (100) GaAs substrates. Two important parameters have been optimized in order to grow high quality QDs with a very good reproducibility: InAs growth rate and GaAs cap layer deposition rate. Atomic force microscopy (AFM) analysis shows a unimodal QD distribution and the room temperature photoluminescence (RTPL) spectrum of the optimized sample reveals a 1.3 μm emission with a 19 meV full width at half maximum (FWHM). Photoluminescence (PL) measurements versus excitation power density and photoluminescence excitation (PLE) measurements clearly show multi-component PL emission from transitions associated with fundamental and related excited states of QDs. Furthermore a good growth reproducibility is observed. The results are promising for further work which will lead to laser fabrication.

Atomic force microscopy of InAs quantum dots on the vicinal surface of a GaAs crystal

2002 ◽  
Vol 28 (2) ◽  
pp. 139-141
Author(s):  
V. P. Evtikhiev ◽  
O. V. Konstantinov ◽  
E. Yu. Kotel’nikov ◽  
A. V. Matveentsev ◽  
A. N. Titkov ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Atomic Force Microscopy ◽  
Vicinal Surface ◽  
Gaas Crystal ◽  
Inas Quantum Dots ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Исследование структурных и люминесцентных свойств гетероструктур InAs/GaAs с легированными Bi потенциальными барьерами

2018 ◽  
Vol 52 (6) ◽  
pp. 581
Author(s):  
А.С. Пащенко ◽  
Л.С. Лунин ◽  
С.Н. Чеботарев ◽  
М.Л. Лунина
Keyword(s):  
Quantum Dots ◽  
Emission Peak ◽  
Structural And Optical Properties ◽  
Inas Quantum Dots ◽  
Force Microscopy ◽  
Potential Barriers ◽  
Atomic Force ◽  
Gaas Barrier ◽  
Gaas Quantum Dot ◽  
Crystal Lattice Parameters

AbstractThe influence of Bi in GaAs barrier layers on the structural and optical properties of InAs/GaAs quantum-dot heterostructures is studied. By atomic-force microscopy and Raman spectroscopy, it is established that the introduction of Bi into GaAs to a content of up to 5 at % results in a decrease in the density of InAs quantum dots from 1.58 × 10^10 to 0.93 × 10^10 cm^–2. The effect is defined by a decrease in the mismatch between the crystal-lattice parameters at the InAs/GaAsBi heterointerface. In this case, an increase in the height of InAs quantum dots is detected. This increase is apparently due to intensification of the surface diffusion of In during growth at the GaAsBi surface. Analysis of the luminescence properties shows that the doping of GaAs potential barriers with Bi is accompanied by a red shift of the emission peak related to InAs quantum dots and by a decrease in the width of this peak.

Optical And Structural properties of Vertical Aligned Self-Assembled InAs Quantum Dots Multilayers

2001 ◽  
Vol 676 ◽  
Author(s):  
J. C. González ◽  
M. I. N. da Silva ◽  
W. N. Rodrigues ◽  
F. M. Matinaga ◽  
R. Magalhaes-Paniago ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Structural Properties ◽  
Molecular Beam ◽  
X Ray Diffraction ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Self Assembled

ABSTRACTIn this work, we report optical and structural properties of vertical aligned self-assembled InAs quantum dots multilayers. The InAs quantum dots samples were grown by Molecular Beam Epitaxy. Employing Atomic Force Microscopy, Transmission Electron Microscopy, and Gracing Incident X-ray Diffraction we have studied the structural properties of samples with different number of periods of the multiplayer structure, as well as different InAs coverage. The optical properties were studied using Photoluminescence spectroscopy.

Assembly and Optical Properties of Metal Nanoparticles

2019 ◽  
Vol 294 ◽  
pp. 3-10
Author(s):  
E.A. Dawi ◽  
A. Abdelkader
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
Self Assembly ◽  
Silicon Oxide ◽  
Ex Situ ◽  
Visible Range ◽  
Plasmonic Nanostructures ◽  
Electromagnetic Spectrum ◽  
Force Microscopy ◽  
Atomic Force

In this paper, the deposition and optical properties of charge-stabilized gold nanoparticles on silicon oxide substrates is studied, which have been derivatised with (aminopropyl) triemethoxysilane. Monodispersed charged-stabilized colloidal gold nanoparticles with diameters between 20-150 nm were prepared and their self-assembly and optical properties on silica substrates is studied. Atomic force microscopy (AFM) is employed to investigate the nanoparticle monolayers ex situ. Analysis of AFM images provide evidence that the formation of the colloidal nanoparticle monolayers is governed by random sequential adsorption. The results indicate that the ionic strength of the suspension influences the spatial distribution of the nanoparticles. For all sizes of the Au nanoparticles tested, optical simulations of extinction coefficients made by finite-difference time domain (FDTD) indicate a resonance peak in the range of 510-600 nm wavelength of the visible range of the electromagnetic spectrum. The results indicate a simple and inexpensive approach of assembly of plasmonic nanostructures that can find applications in metamaterials and light waveguides.

Sign in / Sign up

Export Citation Format

Share Document