Mechanism of the Preferential Edge-Positioning of Self-Organized Ge Quantum Dots on Si Mesas

1999 ◽  
Vol 571 ◽  
Author(s):  
G. Jin ◽  
Y.S. Tang ◽  
J.L. Liu ◽  
S.G. Thomas ◽  
K.L. Wang
Keyword(s):  
Quantum Dots ◽  
Field Distribution ◽  
Strain Field ◽  
Compressive Strain ◽  
Raman Spectroscopic ◽  
Force Microscopy ◽  
Self Organized ◽  
Gas Source ◽  
Atomic Force ◽  
Ge Quantum Dots

ABSTRACTWe have investigated the preferential positioning of self-organized Ge quantum dots on Si (001) mesas fabricated in a selective epitaxial growth (SEG) mode of gas-source molecular beam epitaxy. The surface morphology was evaluated by atomic force microscopy, and for the Si SEG structures, showed mass accumulation at the periphery. Using micro-Raman spectroscopic imaging, the strain-field distribution of Si structures was studied before Ge deposition, and the results suggest a tensile strain at/near the periphery of the structure while a compressive strain at the center. These structures were subsequently used as a template for Ge dots, which tended to align along the mesa edge. The strain field distribution on Si mesas is speculated to be the driving force for preferential nucleation of Ge dots.

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

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.

Evaluation of the Strain Field Inside and Around Growth Islands by Means of X-Ray Diffuse Scattering

1999 ◽  
Vol 583 ◽  
Author(s):  
Martin Schmidbauer ◽  
Thomas Wiebach ◽  
Helmut Raidt ◽  
Peter Schäfer ◽  
Michael hanke ◽  
...  
Keyword(s):  
Strain Field ◽  
Reciprocal Space ◽  
X Ray Diffraction ◽  
Abrupt Increase ◽  
X Ray ◽  
Force Microscopy ◽  
Self Organized ◽  
Atomic Force ◽  
Transmission Electron ◽  
Highly Strained

AbstractThe strain distribution inside and in the vicinity of coherently strained self-organized islands has been investigated by high-resolution x-ray diffraction (HRXRD). Finite element method (FEM) calculations were carried out in order to calculate the strain field, which was then used to simulate x-ray reciprocal space maps on the basis of kinematical scattering theory. For Si0 75Ge0.25 islands an abrupt increase in the Ge-concentration at about one third of the island height has been found. This behavior can be attributed to different nucleation stages during growth. Highly strained buried CdSe quantum dots (QDs) strongly influence the surrounding ZnSe matrix. From reciprocal space maps and FEM simulations we were able to estimate the shape and size of the islands. The results are in agreement with transmission electron microscopy (TEM) and UHV atomic force microscopy (AFM) data.

scholarly journals Density control of InP/GaInP quantum dots grown by metal-organic vapor-phase epitaxy

2018 ◽  
Vol 52 (4) ◽  
pp. 477
Author(s):  
D.V. Lebedev ◽  
N.A. Kalyuzhnyy ◽  
S.A. Mintairov ◽  
K.G. Belyaev ◽  
M.V. Rakhlin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Height Distribution ◽  
Force Microscopy ◽  
Self Organized ◽  
Density Control ◽  
Atomic Force ◽  
Transmission Electron ◽  
Metal Organic

AbstractWe investigated structural and emission properties of self-organized InP/GaInP quantum dots (QD) grown by metal organic chemical vapor deposition using an amount of deposited In from 7 to 2 monolayers (ML). In the uncapped samples, using atomic force microscopy (AFM), we observed lateral sizes of 100–200 nm, together with a bimodal height distribution having maxima at ∼5 and ∼15 nm, which we denoted as QDs of type A and B, respectively; and reduction of the density of the type-B dots from 4.4 to 1.6 μm^–2. The reduction of the density of B-type dots were observed also using transmission electron microscopy of the capped samples. Using single dot low-temperature photoluminescence (PL) spectroscopy we demonstrated effects of Wigner localization for the electrons accumulated in these dots.

Self Organized InAs Quantum Dots on Patterned GaAs Substrates

2005 ◽  
Vol 872 ◽  
Author(s):  
M. Schramboeck ◽  
W. Schrenk ◽  
A. M. Andrews ◽  
T. Roch ◽  
G. Fasching ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Gaas Substrate ◽  
Cross Sectional ◽  
Inas Quantum Dots ◽  
Force Microscopy ◽  
Self Organized ◽  
Atomic Force ◽  
Gaas Substrates ◽  
Vertically Aligned ◽  
Substrate Patterning

AbstractWe investigate the growth of InAs quantum dots on patterned GaAs substrates. The GaAs substrate has been structured using holographic lithography. Quantum dot formation along the patterns has been observed as well as an increase in homogeneity of the quantum dots. Furthermore, the use of ion beams focused to nanometer diameters for substrate patterning has been studied and showed promising results. For the investigation of vertically aligned InAs quantum dots, cross-sectional atomic force microscopy has been successfully employed.

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.

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