scholarly journals Cathodoluminescence Wavelength Imaging Study of Clustering in InAs/GaAs Self-Assembled Quantum Dots

2000 ◽  
Vol 618 ◽  
Author(s):  
D. H. Rich ◽  
C. Zhang ◽  
I. Mukhametzhanov ◽  
A. Madhukar
Keyword(s):  
Quantum Dots ◽  
Spatial Scale ◽  
Size Distribution ◽  
Imaging Study ◽  
Island Growth ◽  
Spectral Lineshape ◽  
Force Microscopy ◽  
Self Organized ◽  
Atomic Force ◽  
Self Assembled

ABSTRACTCathodoluminescence wavelength imaging (CLWI) of InAs/GaAs self-assembled quantum dots (SAQDs) was performed to study the spatial variation in the spectral lineshape of the broadened quantum dot (QD) ensemble. The lineshape was found to vary on a scale of ∼μm, revealing attendant variations in the size distribution of SAQD clusters on this spatial scale. Energy variations in clusters of SAQDs are found to exhibit a spatial correlation with the efficiency of luminescence and the activation energy for thermal re-emission of carriers. A reduction in the energy variation of the QD clusters occurs when the thickness of the spacer layers in vertically self-organized samples is reduced or the number of stacks is increased. SAQDs were also prepared by punctuated island growth (PIG), in which deposition of the total desired amount is broken into two or more stages each separated by time delays. CLWI reveals a reduced variation in the energy of the dominant CL emission on a ∼μm spatial scale, correlating with a narrower size distribution of larger QDs for PIG, as measured in atomic force microscopy.

Uniform dome-shaped self-assembled Ge islands by UHV/CVD after boron pre-deposition

2004 ◽  
Vol 832 ◽  
Author(s):  
Ning Deng ◽  
Wentao Huang ◽  
Peiyi Chen
Keyword(s):  
Quantum Dots ◽  
Size Distribution ◽  
Electronic Devices ◽  
Transition Model ◽  
Shape Transition ◽  
Uniform Size ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ge Quantum Dots ◽  
Self Assembled

AbstratEffect of pre-deposited boron atoms on self-assembled growth of Ge islands on Si(100) substrate by UHV/CVD was investigated by atomic force microscopy (AFM). Proportion of dome-shaped Ge islands increases with the increasing of flux of B2H6. Quite uniform dome-shaped Ge quantum dots with size distribution of less than ±3%, which is narrower than the size distribution of typical bimodal self-assembled Ge dots, were obtained after appropriate boron pre-deposition. Based on the shape transition model we proposed before, the uniform size and shape distributions after boron pre-deposition were explained. The results show that boron pre-deposition can be used to fabricate uniform Ge quantum dots to meet the requirements of opto-electronic devices.

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 and photoluminescence study of Ge layers and self‐organized Ge quantum dots on Si(100)

1996 ◽  
Vol 68 (21) ◽  
pp. 2982-2984 ◽  
Author(s):  
E. Palange ◽  
G. Capellini ◽  
L. Di Gaspare ◽  
F. Evangelisti
Keyword(s):  
Quantum Dots ◽  
Atomic Force Microscopy ◽  
Photoluminescence Study ◽  
Force Microscopy ◽  
Self Organized ◽  
Atomic Force ◽  
Ge Quantum Dots

scholarly journals GROWTH AND PROPERTIES OF STACKED SELF-ASSEMBLED In0.5Ga0.5As QUANTUM DOTS

2012 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Didik Aryanto ◽  
Zulkafli Othaman ◽  
Abd. Khamim Ismail
Keyword(s):  
Quantum Dots ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
The Self ◽  
Organic Chemical ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metal Organic ◽  
Self Assembled ◽  
Organic Chemical Vapor Deposition

Self-assembled In0.5Ga0.5As quantum dots (QDs) were grown using metal-organic chemical vapor deposition (MOCVD) on GaAs (100) substrate with different number of stacking QDs layers. Surface study using atomic force microscopy (AFM) shows that surface morphology of the self-assembled QDs change with different number of stacking QDs layers caused by the previous QDs layers and the thickness of the GaAs spacer layers. PL measurement shows variation in the PL spectra as a function of number of stacking layers of In0.5Ga0.5As QDs. The PL peak positions blue-shifted from 1225 nm to 1095 nm and dramatically increase in intensity with increasing number of stacking QDs layers.

Near Field Optical Spectroscopy of GaN/AlN Quantum Dots

2004 ◽  
Vol 831 ◽  
Author(s):  
A. Neogi ◽  
B. P. Gorman ◽  
H. Morkoç ◽  
T. Kawazoe ◽  
M. Ohtsu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Near Field ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Spacer Layer Thickness ◽  
Spacer Layer ◽  
Lateral Coupling ◽  
Self Assembled ◽  
Spectrally Resolved

ABSTRACTWe investigate the spatial distribution and emission properties of self-assembled GaN/AlN quantum dots. High-resolution transmission electron microscopy reveals near vertical correlation among the GaN dots due to a sufficiently thin AlN spacer layer thickness, which allows strain induced stacking. Scanning electron and atomic force microscopy show lateral coupling due to a surface roughness of ∼ 50–60 nm. Near-field photoluminescence in the illumination mode (both spatially and spectrally resolved) at 10 K revealed emission from individual dots, which exhibits size distribution of GaN dots from localized sites in the stacked nanostructure. Strong spatial localization of the excitons is observed in GaN quantum dots formed at the tip of self-assembled hexagonal pyramid shapes with six [101 1] facets.

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.

Atomic-force microscopy study of self-assembled InAs quantum dots along their complete evolution cycle

2002 ◽  
Vol 241 (1-2) ◽  
pp. 19-30 ◽  
Author(s):  
M.J. da Silva ◽  
A.A. Quivy ◽  
P.P. González-Borrero ◽  
E. Marega ◽  
J.R. Leite
Keyword(s):  
Quantum Dots ◽  
Atomic Force Microscopy ◽  
Microscopy Study ◽  
Atomic Force Microscopy Study ◽  
Inas Quantum Dots ◽  
Force Microscopy ◽  
Atomic Force ◽  
Self Assembled

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

2003 ◽  
Vol 799 ◽  
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.

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