Self-Assembled InAs Lateral Quantum Dot Molecules Growth on (001) GaAs by Thin-Capping-and-Regrowth MBE Technique

2007 ◽  
Vol 121-123 ◽  
pp. 395-400
Author(s):  
S. Suraprapapich ◽  
S. Thainoi ◽  
S. Kanjanachuchai ◽  
S. Panyakeow
Keyword(s):  
Quantum Dot ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Gaas Layer ◽  
Specific Pattern ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial ◽  
Gaas Substrates ◽  
Quantum Dot Molecules ◽  
Self Assembled

InAs lateral quantum dot molecules (QDMs) are grown on (001)-GaAs substrates. The self-assembled QDMs are formed in one continuous molecular beam epitaxial (MBE) growth via a thin-capping-and-regrowth technique. Lateral QDMs, each with 10-12 dots arranged in a specific pattern, are determined by the shapes of the underlying nanopropeller quantum dots (QDs). The nanopropeller QDs in turn are obtained by regrowth on nano-holes which have been previously created by capping the first InAs QD layer grown on (001)-GaAs substrate with a thin GaAs layer. The length of the propeller directly influences the number of QDs in a QDM. By varying the conditions for thin-capping, shorter or longer propellers can be achieved, allowing the number of QDs in each QDM to be controlled.

Fabrication of CdTe Quantum Dot Arrays on GaAs utilizng Nanoporous Alumina Masks

2004 ◽  
Vol 818 ◽  
Author(s):  
Mi Jung ◽  
Hong Seok Lee ◽  
Hong Lee Park ◽  
Sun-Il Mho
Keyword(s):  
Molecular Beam Epitaxy ◽  
Quantum Dot ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Pore Density ◽  
Nanoporous Alumina ◽  
Gaas Substrates ◽  
Cdte Qds ◽  
Self Assembled ◽  
Cdte Quantum Dot

AbstractThe uniformity and reproducibility of the CdTe QD arrays on the GaAs substrates can be improved by using a nanoporous mask. The CdTe QDs on the GaAs substrate were grown by a molecular beam epitaxy (MBE) method. The nanoporous alumina masks used for the fabrication of QD arrays have the thickness from 0.3 νm to 5 νm with the nanochannels of ∼ 80 nm diameter and the pore density of ∼ 1010cm−2. When the thickness of the alumina mask used for the CdTe QD growth was about 300 nm, the CdTe QD arrays formed as a replica of the nanochannels of the mask. Smaller self-assembled CdTe QDs located randomly were produced by using the thicker nanochannel mask than 0.5 νm. The thickness of the nanochannel mask controls the size of the CdTe/GaAs QDs.

Evolution of self-assembled InAs quantum dot molecules by molecular beam epitaxy

2012 ◽  
Vol 9 (7) ◽  
pp. 1534-1536 ◽  
Author(s):  
Ong-arj Tangmettajittakul ◽  
Supachok Thainoi ◽  
Somsak Panyakeow ◽  
Somchai Ratanathammaphan
Keyword(s):  
Molecular Beam Epitaxy ◽  
Quantum Dot ◽  
Molecular Beam ◽  
Quantum Dot Molecules ◽  
Self Assembled ◽  
Inas Quantum Dot

Band Edge Optical Absorption of Molecular Beam Epitaxial GaSb Grown on Semi-Insulating GaAs Substrate

1993 ◽  
Vol 325 ◽  
Author(s):  
M. Shah ◽  
M.O. Manasreh ◽  
R. Kaspi ◽  
M. Y. Yen ◽  
B. A. Philips ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Optical Absorption ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Free Exciton ◽  
Buffer Layers ◽  
Band Edge ◽  
Exciton Absorption ◽  
Molecular Beam Epitaxial ◽  
Gaas Substrates

AbstractThe optical absorption of the band edge of GaSb layers grown on semi-insulating GaAs substrates by the molecular beam epitaxy (MBE) technique is studied as a function of temperature. A free exciton absorption peak at 0.807 eV was observed at 10 K. The free exciton line is observed in either thick samples (5μm thick) or samples with ∼0.1 μm thick AlSb buffer layers. The latter samples suggest that the AlSb buffer layer is very effective in preventing some of the dislocations from propagating into the MBE GaSb layers. The fitting of the band gap of the GaSb layers as a function of temperature gives a Debye temperature different than that of the bulk GaSb calculated from the elastic constants.

Stacking of InAs QDs with Different Spacer Layer Thickness on GaAs Substrate by Molecular Beam Epitaxy

2018 ◽  
Vol 24 (8) ◽  
pp. 5574-5577
Author(s):  
S Saravanan
Keyword(s):  
Layer Thickness ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Single Layer ◽  
Areal Density ◽  
Gaas Layer ◽  
Peak Position ◽  
Molecular Beam Epitaxial ◽  
Spacer Layer Thickness ◽  
Spacer Layer

InAs QDs were grown by supplying 2.5 mono-layers (MLs) of InAs at 500 °C in a molecular beam epitaxial (MBE) system. The QDs are approximately 4–6 nm height with an areal density of 3×85 ×1010 cm−2 for single layer QDs. Typical diameter was found to be about 15–25 nm. InAs QDs were stacked with the spacer layer thickness of 5, 10, 15, 25 and 35 nm. For 15 nm of spacer layer thickness the QDs density decreased to 2.62×1010 cm−2 and again increased for 35 nm spacer layer and reached to the value of 3.65×1010 cm−2. The 14 K photoluminescence (PL) spectra of single layer InAs QDs covered by GaAs layer centered at 1079 nm. For the stacking of InAs QDs with spacer layer thickness of 5 and 10 nm another peak appeared around 1100 nm due to size broadening of QDs because of strain propagation to next layer due to less thickness of spacer layer. When the thickness of the spacer layer increased to 35 nm the peak position is around 1073 nm and the intensity increased more than 3 fold when compare to single layer QDs.

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