Investigation of GaSb/GaAs Quantum Dots Formation on Ge (001) Substrate and Effect of Anti-Phase Domains

MRS Advances ◽  
2016 ◽  
Vol 1 (23) ◽  
pp. 1729-1734 ◽  
Author(s):  
Zon ◽  
Thanavorn Poempool ◽  
Suwit Kiravittaya ◽  
Suwat Sopitpan ◽  
Supachok Thainoi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Buffer Layer ◽  
Growth Temperature ◽  
Molecular Beam ◽  
Sample Surface ◽  
Layer Growth ◽  
Group Iv ◽  
Optimum Conditions ◽  
Molecular Beam Epitaxial ◽  
Molecular Beam Epitaxial Growth

ABSTRACTThe effects of GaAs anti-phase domains (APDs) on the growth of GaSb quantum dots (QDs) are investigated by molecular beam epitaxial growth of GaAs on Ge (001) substrate. Ge is a group-IV element and GaAs is a polar III-V compound semiconductor. Due to polar/non polar interface, GaAs APDs are formed. Initial formation of APD relates to a non-uniform growth of high index GaAs surfaces. However, due to high sticking coefficient of Sb atoms at low substrate growth temperature, GaSb QDs can be formed on the whole surface of the sample without any effects from APD boundary. The buffer layer growth temperature is one of the key roles to control the APDs formation. Therefore we tried to adjust the optimum conditions such as buffer layer thickness and growth temperature to get nearly flat sample surface with large APDs for high QDs density (∼ 8×109 dots/cm2). Low-temperature photoluminescence is conducted and GaSb QDs peak is observed at the energy range of 1.0 eV-1.3 eV.

Molecular beam epitaxial growth of InAs self-assembled quantum dots with light-emission at 1.3μm

2000 ◽  
Vol 208 (1-4) ◽  
pp. 93-99 ◽  
Author(s):  
Y Nakata ◽  
K Mukai ◽  
M Sugawara ◽  
K Ohtsubo ◽  
H Ishikawa ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
Light Emission ◽  
Molecular Beam Epitaxial ◽  
Self Assembled ◽  
Molecular Beam Epitaxial Growth

Self-assembled quantum dots and nanoholes by molecular beam epitaxial growth and atomically precise in situ etching

2002 ◽  
Vol 722 ◽  
Author(s):  
S. Kiravittaya ◽  
R. Songmuang ◽  
O. G. Schmidt
Keyword(s):  
Quantum Dots ◽  
Molecular Beam ◽  
Flat Surface ◽  
Local Strain ◽  
Growth Conditions ◽  
Etching Depth ◽  
Molecular Beam Epitaxial ◽  
Self Assembled ◽  
Molecular Beam Epitaxial Growth

AbstractEnsembles of homogeneous self-assembled quantum dots (QDs) and nanoholes are fabricated using molecular beam epitaxy in combination with atomically precise in situ etching. Self-assembled InAs QDs with height fluctuations of ±5% were grown using a very low indium growth rate on GaAs (001) substrate. If these dots are capped with GaAs at low temperature, strong room temperature emission at 1.3 νm with a linewidth of 21 meV from the islands is observed. Subsequently, we fabricate homogeneous arrays of nanoholes by in situ etching the GaAs surface of the capped InAs QDs with AsBr3. The depths of the nanoholes can be tuned over a range of 1-6 nm depending on the nominal etching depth and the initial capping layer thickness. We appoint the formation of nanoholes to a pronounced selectivity of the AsBr3 to local strain fields. The holes can be filled with InAs again such that an atomically flat surface is recovered. QDs in the second layer preferentially form at those sites, where the holes were initially created. Growth conditions for the second InAs layer can be chosen in such a way that lateral QD molecules form on a flat surface.

Impact of Buffered Layer Growth Conditions on Grown-In Vacancy Concentrations in Molecular Beam Epitaxy Silicon Germanium

2004 ◽  
Vol 809 ◽  
Author(s):  
Kareem M. Shoukri ◽  
Yaser M. Haddara ◽  
Andrew P. Knights ◽  
Paul G. Coleman ◽  
Mohammad M. Rahman ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Point Defects ◽  
Growth Temperature ◽  
Silicon Germanium ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Layer Growth ◽  
Vacancy Clusters ◽  
Temperature And Growth

ABSTRACTSilicon-Germanium (SiGe) has become increasingly attractive to semiconductor manufacturers over the last decade for use in high performance devices. In order to produce thin layers of device grade SiGe with low concentrations of point defects and well-controlled doping profiles, advanced growth and deposition techniques such as molecular beam epitaxy (MBE) are used. One of the key issues in modeling dopant diffusion during subsequent processing is the concentration of grown-in point defects. The incorporation of vacancy clusters and vacancy point defects in 200nm SiGe/Si layers grown by molecular beam epitaxy over different buffer layers has been observed using beam-based positron annihilation spectroscopy. Variables included the type of buffer layer, the growth temperature and growth rate for the buffer, and the growth temperature and growth rate for the top layer. Different growth conditions resulted in different relaxation amounts in the top layer, but in all samples the dislocation density was below 106 cm−2. Preliminary results indicate a correlation between the size, type and concentration of vacancy defects and the buffer layer growth temperature. At high buffer layer growth temperature of 500°C the vacancy point defect concentration is below the PAS detectable limit of approximately 1015 cm−3. As the buffer layer growth is decreased to a minimum value of 300°C, large vacancy clusters are observed in the buffered layer and vacancy point defects are observed in the SiGe film. These results are relevant to the role played by point defects grown-in at temperatures below ∼350°C in modeling dopant diffusion during processing.

Molecular beam epitaxial growth of interdigitated quantum dots for heterojunction solar cells

2019 ◽  
Vol 512 ◽  
pp. 159-163 ◽  
Author(s):  
C. Chevuntulak ◽  
T. Rakpaises ◽  
N. Sridumrongsak ◽  
S. Thainoi ◽  
S. Kiravittaya ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
Heterojunction Solar Cells ◽  
Molecular Beam Epitaxial ◽  
Molecular Beam Epitaxial Growth
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