Professor Somsak Panyakeow, D. Eng.
ศ. ดร.สมศักดิ์ ปัญญาแก้ว
Education
- D. Eng. (Electrical), Osaka University, Japan.1974
- M. Eng. (Electrical), Osaka University, Japan.1971
- B. Eng. (Electrical), Osaka University, Japan.1969
Email: Somsak.P@chula.ac.th
Research Interest
- Solar Cells and Photovoltaic Applications
- Laser Engineering
- Optoelectronics
- Quantum Devices and Nanoelectronics
Research Cluster
51.
Boonpeng, P; Jevasuwan, W; Suraprapapich, S; Ratanathammaphan, S; Panyakeow, S
Quadra-quantum dots grown on quantum rings having square-shaped holes: Basic nanostructure for quantum dot cellular automata application Journal Article
In: Microelectronic Engineering, vol. 86, no. 4-6, pp. 853-856, 2009, ISSN: 01679317, (cited By 17).
@article{Boonpeng2009,
title = {Quadra-quantum dots grown on quantum rings having square-shaped holes: Basic nanostructure for quantum dot cellular automata application},
author = {P Boonpeng and W Jevasuwan and S Suraprapapich and S Ratanathammaphan and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349259320&doi=10.1016%2fj.mee.2008.12.027&partnerID=40&md5=5af843ea904d45a2c0381ce0a9abc543},
doi = {10.1016/j.mee.2008.12.027},
issn = {01679317},
year = {2009},
date = {2009-01-01},
journal = {Microelectronic Engineering},
volume = {86},
number = {4-6},
pages = {853-856},
abstract = {Preferable quantum dot (QD) nanostructure for quantum computation based on quantum cellular automata (QCA) is laterally close-packed quantum dot molecular (QDM) having 4 QDs at the corners of square configuration. We called this 4 QDs-set as quadra-quantum dots (QQDs). Aligned QQDs with 2 electron-confinements work like a wire for digital information transmission by Coulomb repulsion force which is high speed and consumes little power. Combination of QQDs in line and their cross-over work as logic gates and memory bits. We have developed a Molecular Beam Epitaxial (MBE) growth technique call "Droplet Epitaxy" for several quantum nanostructures such as quantum rings (QRs), quantum dot rings (QDRs). In this presentation, we prepare QRs with 20 ML In-Ga (15:85) droplet at 390 °C and droplet growth rate of 1ML/s. Arsenic flux (7-8 × 10-6 Torr) is then exposed for InGaAs crystallization at 200 °C for 5 min. During droplet epitaxy at high value of droplet thickness and high temperature, out-diffusion from the centre of droplets occurs under anisotropic stain. This leads to quantum ring structures having non-uniform ring stripes and deep square-shaped nanoholes. Using these peculiar QRs as templates, 4 QDs situating at each corner of square shape are regrown. Two of these 4 QDs are aligned either [1over(1, ̄) 0] or [1 1 0] which are preferable crystallographic directions of QD alignment in general. © 2009 Elsevier B.V. All rights reserved.},
note = {cited By 17},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Preferable quantum dot (QD) nanostructure for quantum computation based on quantum cellular automata (QCA) is laterally close-packed quantum dot molecular (QDM) having 4 QDs at the corners of square configuration. We called this 4 QDs-set as quadra-quantum dots (QQDs). Aligned QQDs with 2 electron-confinements work like a wire for digital information transmission by Coulomb repulsion force which is high speed and consumes little power. Combination of QQDs in line and their cross-over work as logic gates and memory bits. We have developed a Molecular Beam Epitaxial (MBE) growth technique call "Droplet Epitaxy" for several quantum nanostructures such as quantum rings (QRs), quantum dot rings (QDRs). In this presentation, we prepare QRs with 20 ML In-Ga (15:85) droplet at 390 °C and droplet growth rate of 1ML/s. Arsenic flux (7-8 × 10-6 Torr) is then exposed for InGaAs crystallization at 200 °C for 5 min. During droplet epitaxy at high value of droplet thickness and high temperature, out-diffusion from the centre of droplets occurs under anisotropic stain. This leads to quantum ring structures having non-uniform ring stripes and deep square-shaped nanoholes. Using these peculiar QRs as templates, 4 QDs situating at each corner of square shape are regrown. Two of these 4 QDs are aligned either [1over(1, ̄) 0] or [1 1 0] which are preferable crystallographic directions of QD alignment in general. © 2009 Elsevier B.V. All rights reserved.
52.
Pankaow, N; Panyakeow, S; Ratanathammaphan, S
Formation of In0.5Ga0.5As ring-and-hole structure by droplet molecular beam epitaxy Journal Article
In: Journal of Crystal Growth, vol. 311, no. 7, pp. 1832-1835, 2009, ISSN: 00220248, (cited By 19).
@article{Pankaow2009,
title = {Formation of In0.5Ga0.5As ring-and-hole structure by droplet molecular beam epitaxy},
author = {N Pankaow and S Panyakeow and S Ratanathammaphan},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-63349093931&doi=10.1016%2fj.jcrysgro.2008.11.003&partnerID=40&md5=407e09ae4215ed4eb0b011345bf97e56},
doi = {10.1016/j.jcrysgro.2008.11.003},
issn = {00220248},
year = {2009},
date = {2009-01-01},
journal = {Journal of Crystal Growth},
volume = {311},
number = {7},
pages = {1832-1835},
abstract = {Fabrication of InGaAs ring-and-hole nanostructures was successfully demonstrated by the droplet epitaxy technique using molecular beam epitaxy (MBE). The evolution of surface morphology during growth was monitored in situ by reflection high-energy electron diffraction (RHEED). Droplet-forming conditions were changed by varying substrate temperatures during In0.5Ga0.5 deposition (so-called deposition temperature). Dependence of the ring structural properties on the deposition temperature was investigated. Distributions of InGaAs ring outer diameter, outer height, and inner depth at different deposition temperatures were also examined. It was found that the higher the deposition temperatures, the larger the outer diameter and the higher the outer height of most of the InGaAs rings. However, they had slightly lower densities. Photoluminescence results confirmed the high quality of the nanocrystal. © 2008 Elsevier B.V. All rights reserved.},
note = {cited By 19},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Fabrication of InGaAs ring-and-hole nanostructures was successfully demonstrated by the droplet epitaxy technique using molecular beam epitaxy (MBE). The evolution of surface morphology during growth was monitored in situ by reflection high-energy electron diffraction (RHEED). Droplet-forming conditions were changed by varying substrate temperatures during In0.5Ga0.5 deposition (so-called deposition temperature). Dependence of the ring structural properties on the deposition temperature was investigated. Distributions of InGaAs ring outer diameter, outer height, and inner depth at different deposition temperatures were also examined. It was found that the higher the deposition temperatures, the larger the outer diameter and the higher the outer height of most of the InGaAs rings. However, they had slightly lower densities. Photoluminescence results confirmed the high quality of the nanocrystal. © 2008 Elsevier B.V. All rights reserved.
53.
Boonpeng, P; Panyakeow, S; Ratanathammaphan, S
Fabrication of In0.15Ga0.85As nanohloes on GaAs by droplet molecular beam epitaxy Journal Article
In: Journal of Crystal Growth, vol. 311, no. 7, pp. 1843-1846, 2009, ISSN: 00220248, (cited By 1).
@article{Boonpeng2009a,
title = {Fabrication of In0.15Ga0.85As nanohloes on GaAs by droplet molecular beam epitaxy},
author = {P Boonpeng and S Panyakeow and S Ratanathammaphan},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-63349093032&doi=10.1016%2fj.jcrysgro.2008.10.066&partnerID=40&md5=206984df31031eb7c20c92a964642f0c},
doi = {10.1016/j.jcrysgro.2008.10.066},
issn = {00220248},
year = {2009},
date = {2009-01-01},
journal = {Journal of Crystal Growth},
volume = {311},
number = {7},
pages = {1843-1846},
abstract = {This article reports on the fabrication of self-assembled In0.15Ga0.85As nanoholes on GaAs(1 0 0)substrates grown by droplet epitaxy using molecular beam epitaxy. The effects of growth interruption time and substrate temperature were investigated. The surface morphology of In0.15Ga0.85As nanoholes were examined by atomic force microscopy. The results show the dependence of density, depth, and width of nanoholes on the growth interruption time and substrate temperature. This growth technique is simple and flexible. It does not require additional complicated substrate processing and has a potential in developing quantum dots and quantum dot molecules for quantum computation applications. © 2008 Elsevier B.V. All rights reserved.},
note = {cited By 1},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This article reports on the fabrication of self-assembled In0.15Ga0.85As nanoholes on GaAs(1 0 0)substrates grown by droplet epitaxy using molecular beam epitaxy. The effects of growth interruption time and substrate temperature were investigated. The surface morphology of In0.15Ga0.85As nanoholes were examined by atomic force microscopy. The results show the dependence of density, depth, and width of nanoholes on the growth interruption time and substrate temperature. This growth technique is simple and flexible. It does not require additional complicated substrate processing and has a potential in developing quantum dots and quantum dot molecules for quantum computation applications. © 2008 Elsevier B.V. All rights reserved.
54.
Suraprapapich, S; Shen, Y M; Fainman, Y; Horikoshi, Y; Panyakeow, S; Tu, C W
The effects of rapid thermal annealing on doubled quantum dots grown by molecular beam epitaxy Journal Article
In: Journal of Crystal Growth, vol. 311, no. 7, pp. 1791-1794, 2009, ISSN: 00220248, (cited By 6).
@article{Suraprapapich2009,
title = {The effects of rapid thermal annealing on doubled quantum dots grown by molecular beam epitaxy},
author = {S Suraprapapich and Y M Shen and Y Fainman and Y Horikoshi and S Panyakeow and C W Tu},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-63549119433&doi=10.1016%2fj.jcrysgro.2008.12.037&partnerID=40&md5=f1af8add2df18fed2be467c63e2a9300},
doi = {10.1016/j.jcrysgro.2008.12.037},
issn = {00220248},
year = {2009},
date = {2009-01-01},
journal = {Journal of Crystal Growth},
volume = {311},
number = {7},
pages = {1791-1794},
abstract = {The effects of different rapid thermal annealing temperatures on the optical properties of InAs double quantum dots (DQDs) grown by molecular beam epitaxy using a partial-capping-and-regrowth process have been investigated. Improvement of the material quality is indicated by enhanced photoluminescence (PL) intensity and narrower PL linewidth. The blueshift of the PL emission peak with increasing annealing temperature is due to the interdiffusion of group III atoms during the annealing process, which is confirmed by the temperature dependence of the PL peak position. Thermal quenching of the PL intensity is observed at temperature over 110 K, and the main activation energy decreases with annealing temperature, consistent with a reduced confining potential from the interdiffusion of group III atoms. All of these results are similar to those of single quantum dots reported in the literature. © 2008 Elsevier B.V.},
note = {cited By 6},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The effects of different rapid thermal annealing temperatures on the optical properties of InAs double quantum dots (DQDs) grown by molecular beam epitaxy using a partial-capping-and-regrowth process have been investigated. Improvement of the material quality is indicated by enhanced photoluminescence (PL) intensity and narrower PL linewidth. The blueshift of the PL emission peak with increasing annealing temperature is due to the interdiffusion of group III atoms during the annealing process, which is confirmed by the temperature dependence of the PL peak position. Thermal quenching of the PL intensity is observed at temperature over 110 K, and the main activation energy decreases with annealing temperature, consistent with a reduced confining potential from the interdiffusion of group III atoms. All of these results are similar to those of single quantum dots reported in the literature. © 2008 Elsevier B.V.
55.
Swe, N C; Tangmattajittakul, O; Suraprapapich, S; Changmoang, P; Thainoi, S; Wissawinthanon, C; Kanjanachuchai, S; Ratanathammaphan, S; Panyakeow, S
In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, vol. 26, no. 3, pp. 1100-1104, 2008, ISSN: 10711023, (cited By 3).
@article{Swe2008,
title = {Improved quantum confinement of self-assembled high-density InAs quantum dot molecules in AlGaAsGaAs quantum well structures by molecular beam epitaxy},
author = {N C Swe and O Tangmattajittakul and S Suraprapapich and P Changmoang and S Thainoi and C Wissawinthanon and S Kanjanachuchai and S Ratanathammaphan and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-44649158210&doi=10.1116%2f1.2835064&partnerID=40&md5=b01ab372f6260712583b3c271e795c30},
doi = {10.1116/1.2835064},
issn = {10711023},
year = {2008},
date = {2008-01-01},
journal = {Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures},
volume = {26},
number = {3},
pages = {1100-1104},
abstract = {Self-assembled, multistack InAs quantum dot molecules (QDMs) were grown by a modified molecular beam epitaxial (MBE) technique, which involves multiple stacking and multiple cycling of the thin-capping-and-regrowth process, so as to obtain a large volume density of quantum dots on the sample. Furthermore, the high-density InAs QDMs were also grown sandwiched either between a double heterostructure (DHS) or between a quantum-well (QW) structure. It was found from microphotoluminescence (μ -PL) measurements that the QDMs sandwiched between these structures give broader PL spectra than those of the as-grown QDMs. The broadening of the PL spectra is associated with the poorer dot size uniformity, which arises from the long and complicated MBE growth processes. However, comparing between the QDMs in the DHS and in the QW structure, the latter give narrower PL spectra. The narrower PL spectra for the QDM-in-QW structure is attributed to the improved quantum confinement effect arising from the use of the QW. © 2008 American Vacuum Society.},
note = {cited By 3},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Self-assembled, multistack InAs quantum dot molecules (QDMs) were grown by a modified molecular beam epitaxial (MBE) technique, which involves multiple stacking and multiple cycling of the thin-capping-and-regrowth process, so as to obtain a large volume density of quantum dots on the sample. Furthermore, the high-density InAs QDMs were also grown sandwiched either between a double heterostructure (DHS) or between a quantum-well (QW) structure. It was found from microphotoluminescence (μ -PL) measurements that the QDMs sandwiched between these structures give broader PL spectra than those of the as-grown QDMs. The broadening of the PL spectra is associated with the poorer dot size uniformity, which arises from the long and complicated MBE growth processes. However, comparing between the QDMs in the DHS and in the QW structure, the latter give narrower PL spectra. The narrower PL spectra for the QDM-in-QW structure is attributed to the improved quantum confinement effect arising from the use of the QW. © 2008 American Vacuum Society.
56.
Thet, C C; Sanorpim, S; Panyakeow, S; Kanjanachuchai, S
The effects of relaxed InGaAs virtual substrates on the formation of self-assembled InAs quantum dots Journal Article
In: Semiconductor Science and Technology, vol. 23, no. 5, 2008, ISSN: 02681242, (cited By 7).
@article{Thet2008,
title = {The effects of relaxed InGaAs virtual substrates on the formation of self-assembled InAs quantum dots},
author = {C C Thet and S Sanorpim and S Panyakeow and S Kanjanachuchai},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-43149116326&doi=10.1088%2f0268-1242%2f23%2f5%2f055007&partnerID=40&md5=04f385247714ba0b1337a8f7b3eb89be},
doi = {10.1088/0268-1242/23/5/055007},
issn = {02681242},
year = {2008},
date = {2008-01-01},
journal = {Semiconductor Science and Technology},
volume = {23},
number = {5},
abstract = {Self-assembled InAs quantum dots (QDs) are grown on InGaAs/GaAs virtual substrates (VS) by molecular beam epitaxy. By growing InAs QDs on partially relaxed InGaAs layers with different thicknesses, hence with varying degrees of relaxation, we obtain InAs QDs which are aligned or grouped into distinct units. It was found that growths of InAs QDs on these VS result in preferential alignment along [1 1 0] and [1 -1 0] directions, and the thicker the InGaAs relaxed layer the higher the chance that QDs coalesce into distinct ensembles of QDs. We attribute the results to the difference in the underlying surface undulation due to different degrees of VS relaxation and to strain asymmetries, as confirmed by atomic force microscopy and high-resolution x-ray diffraction. A schematic description of InAs QD growth on partially relaxed InGaAs layers is given. © 2008 IOP Publishing Ltd.},
note = {cited By 7},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Self-assembled InAs quantum dots (QDs) are grown on InGaAs/GaAs virtual substrates (VS) by molecular beam epitaxy. By growing InAs QDs on partially relaxed InGaAs layers with different thicknesses, hence with varying degrees of relaxation, we obtain InAs QDs which are aligned or grouped into distinct units. It was found that growths of InAs QDs on these VS result in preferential alignment along [1 1 0] and [1 -1 0] directions, and the thicker the InGaAs relaxed layer the higher the chance that QDs coalesce into distinct ensembles of QDs. We attribute the results to the difference in the underlying surface undulation due to different degrees of VS relaxation and to strain asymmetries, as confirmed by atomic force microscopy and high-resolution x-ray diffraction. A schematic description of InAs QD growth on partially relaxed InGaAs layers is given. © 2008 IOP Publishing Ltd.
57.
Boonpeng, P; Panyakeow, S; Ratanathammaphan, S
In-mole-fraction and thickness of ultra-thin InGaAs Insertion layers effects on the structural and optical properties of InAs quantum dots Journal Article
In: Advanced Materials Research, vol. 31, pp. 132-134, 2008, ISSN: 10226680, (cited By 0; Conference of International Conference on Materials for Advanced Technologies, ICMAT 2007 ; Conference Date: 1 July 2007 Through 6 July 2007; Conference Code:72337).
@article{Boonpeng2008,
title = {In-mole-fraction and thickness of ultra-thin InGaAs Insertion layers effects on the structural and optical properties of InAs quantum dots},
author = {P Boonpeng and S Panyakeow and S Ratanathammaphan},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-45749132254&doi=10.4028%2f0-87849-471-5.132&partnerID=40&md5=31d749fcc2214b755f6858330cdccc52},
doi = {10.4028/0-87849-471-5.132},
issn = {10226680},
year = {2008},
date = {2008-01-01},
journal = {Advanced Materials Research},
volume = {31},
pages = {132-134},
publisher = {Trans Tech Publications},
abstract = {InAs quantum dots (QDs) have been grown by solid-source molecular beam epitaxy on different InxGa1-xAs (0 ≤ x ≤ 0.3) to investigate the effect of In-mole-fraction and thickness of InGaAs insertion layer (IL) on the structural and optical properties of the QDs. The density of QDs directly grown on GaAs is 1 × 1010 cm-2, and increase to 1.4-1.8×1010 cm-2 on InGaAs layers which depend on the In-mole-fraction and thickness of InGaAs layers. The effects of In-mole-fraction and thickness of InGaAs insertion layer on optical properties of the QDs are studied by photoluminescence (PL). The FWHM of PL spectrum corresponds to the size distribution of the QDs.},
note = {cited By 0; Conference of International Conference on Materials for Advanced Technologies, ICMAT 2007 ; Conference Date: 1 July 2007 Through 6 July 2007; Conference Code:72337},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
InAs quantum dots (QDs) have been grown by solid-source molecular beam epitaxy on different InxGa1-xAs (0 ≤ x ≤ 0.3) to investigate the effect of In-mole-fraction and thickness of InGaAs insertion layer (IL) on the structural and optical properties of the QDs. The density of QDs directly grown on GaAs is 1 × 1010 cm-2, and increase to 1.4-1.8×1010 cm-2 on InGaAs layers which depend on the In-mole-fraction and thickness of InGaAs layers. The effects of In-mole-fraction and thickness of InGaAs insertion layer on optical properties of the QDs are studied by photoluminescence (PL). The FWHM of PL spectrum corresponds to the size distribution of the QDs.
58.
Pankaow, N; Panyakeow, S; Ratanathammaphan, S
Nanometer-scale in0.5Ga0.5As ring-like structure grown by droplet epitaxy Journal Article
In: Advanced Materials Research, vol. 31, pp. 123-125, 2008, ISSN: 10226680, (cited By 4; Conference of International Conference on Materials for Advanced Technologies, ICMAT 2007 ; Conference Date: 1 July 2007 Through 6 July 2007; Conference Code:72337).
@article{Pankaow2008,
title = {Nanometer-scale in0.5Ga0.5As ring-like structure grown by droplet epitaxy},
author = {N Pankaow and S Panyakeow and S Ratanathammaphan},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-45749132249&doi=10.4028%2f0-87849-471-5.123&partnerID=40&md5=52017e5fced170380610625114e50d59},
doi = {10.4028/0-87849-471-5.123},
issn = {10226680},
year = {2008},
date = {2008-01-01},
journal = {Advanced Materials Research},
volume = {31},
pages = {123-125},
publisher = {Trans Tech Publications},
abstract = {We have demonstrated the fabrication of InGaAs ring-like nanostructures by droplet-epitaxy technique using molecular-beam epitaxy. Dependence on the substrate temperature and the amount of indium and gallium of the nanostructural properties was investigated. It was found that increasing substrate temperature resulted in larger InGaAs ring size but with lower density and that increasing In0.5Ga0.5 amount resulted in larger InGaAs ring size but with oscillating density. Photoluminescence results confirmed the high quality of the nanocrystal.},
note = {cited By 4; Conference of International Conference on Materials for Advanced Technologies, ICMAT 2007 ; Conference Date: 1 July 2007 Through 6 July 2007; Conference Code:72337},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We have demonstrated the fabrication of InGaAs ring-like nanostructures by droplet-epitaxy technique using molecular-beam epitaxy. Dependence on the substrate temperature and the amount of indium and gallium of the nanostructural properties was investigated. It was found that increasing substrate temperature resulted in larger InGaAs ring size but with lower density and that increasing In0.5Ga0.5 amount resulted in larger InGaAs ring size but with oscillating density. Photoluminescence results confirmed the high quality of the nanocrystal.
59.
Jewasuwan, W; Panyakeow, S; Ratanathammaphan, S
The formation of InP ring-shape nanostructures on in0.49Ga 0.51P grown by droplet epitaxy Journal Article
In: Advanced Materials Research, vol. 31, pp. 158-160, 2008, ISSN: 10226680, (cited By 0; Conference of International Conference on Materials for Advanced Technologies, ICMAT 2007 ; Conference Date: 1 July 2007 Through 6 July 2007; Conference Code:72337).
@article{Jewasuwan2008,
title = {The formation of InP ring-shape nanostructures on in0.49Ga 0.51P grown by droplet epitaxy},
author = {W Jewasuwan and S Panyakeow and S Ratanathammaphan},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-45749104144&doi=10.4028%2f0-87849-471-5.158&partnerID=40&md5=e5b262f41dd81374c23b1f3e843e9b18},
doi = {10.4028/0-87849-471-5.158},
issn = {10226680},
year = {2008},
date = {2008-01-01},
journal = {Advanced Materials Research},
volume = {31},
pages = {158-160},
publisher = {Trans Tech Publications},
abstract = {We report on the fabrication of self-assembled InP ring-shape nanostructures on In0.49Ga0.51P by droplet molecular-beam epitaxy. The dependency of InP ring-shape nanostructural properties on substrate temperature and indium deposition rate is investigated by ex situ atomic force microscope (AFM). The nano-craters are formed when indium deposition at 120°C while the ring shape quantum-dot molecules are formed when indium deposition at 150°C or higher. The size, density and pattern of InP ring-shape nanostructures strongly depend on substrate temperature and indium deposition rate during indium deposition.},
note = {cited By 0; Conference of International Conference on Materials for Advanced Technologies, ICMAT 2007 ; Conference Date: 1 July 2007 Through 6 July 2007; Conference Code:72337},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on the fabrication of self-assembled InP ring-shape nanostructures on In0.49Ga0.51P by droplet molecular-beam epitaxy. The dependency of InP ring-shape nanostructural properties on substrate temperature and indium deposition rate is investigated by ex situ atomic force microscope (AFM). The nano-craters are formed when indium deposition at 120°C while the ring shape quantum-dot molecules are formed when indium deposition at 150°C or higher. The size, density and pattern of InP ring-shape nanostructures strongly depend on substrate temperature and indium deposition rate during indium deposition.
60.
Suraprapapich, S; Thainoi, S; Kanjanachuchai, S; Panyakeow, S
Self-assembled InAs lateral quantum dot molecules growth on (001) GaAs by thin-capping-and-regrowth MBE technique Journal Article
In: Solid State Phenomena, vol. 121-123, no. PART 1, pp. 395-400, 2007, ISSN: 10120394, (cited By 0; Conference of China International Conference on Nanoscience and Technology, ChinaNANO 2005 ; Conference Date: 9 June 2005 Through 11 June 2005; Conference Code:71325).
@article{Suraprapapich2007,
title = {Self-assembled InAs lateral quantum dot molecules growth on (001) GaAs by thin-capping-and-regrowth MBE technique},
author = {S Suraprapapich and S Thainoi and S Kanjanachuchai and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38549178082&doi=10.4028%2f3-908451-30-2.395&partnerID=40&md5=86a786ec19b2aecfe4a711dfa4c8ec0c},
doi = {10.4028/3-908451-30-2.395},
issn = {10120394},
year = {2007},
date = {2007-01-01},
journal = {Solid State Phenomena},
volume = {121-123},
number = {PART 1},
pages = {395-400},
publisher = {Trans Tech Publications Ltd},
address = {Beijing},
abstract = {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.},
note = {cited By 0; Conference of China International Conference on Nanoscience and Technology, ChinaNANO 2005 ; Conference Date: 9 June 2005 Through 11 June 2005; Conference Code:71325},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
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.
61.
Suraprapapich, S; Panyakeow, S; Tu, C W
Effect of arsenic species on the formation of (Ga)InAs nanostructures after partial capping and regrowth Journal Article
In: Applied Physics Letters, vol. 90, no. 18, 2007, ISSN: 00036951, (cited By 37).
@article{Suraprapapich2007a,
title = {Effect of arsenic species on the formation of (Ga)InAs nanostructures after partial capping and regrowth},
author = {S Suraprapapich and S Panyakeow and C W Tu},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34247895679&doi=10.1063%2f1.2735676&partnerID=40&md5=091be93f888b0fa7c68e725d505e684d},
doi = {10.1063/1.2735676},
issn = {00036951},
year = {2007},
date = {2007-01-01},
journal = {Applied Physics Letters},
volume = {90},
number = {18},
abstract = {Surface morphologies of self-assembled (Ga)InAs nanostructures grown by partial-capping-and-regrowth technique using gas-source molecular beam epitaxy (GSMBE) and solid-source molecular beam epitaxy (SSMBE) are compared. With SSMBE under an As4 ambient, as-grown quantum dots (QDs) change to a camel-like nanostructure after being partially overgrown with GaAs. When additional InAs is deposited, quantum-dot molecules are created. In comparison, with GSMBE under As2 overpressure, as-grown QDs are transformed into quantum rings after partial capping with GaAs and then, after regrowth, become double QDs. At higher regrowth temperature, QD rings are formed. © 2007 American Institute of Physics.},
note = {cited By 37},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Surface morphologies of self-assembled (Ga)InAs nanostructures grown by partial-capping-and-regrowth technique using gas-source molecular beam epitaxy (GSMBE) and solid-source molecular beam epitaxy (SSMBE) are compared. With SSMBE under an As4 ambient, as-grown quantum dots (QDs) change to a camel-like nanostructure after being partially overgrown with GaAs. When additional InAs is deposited, quantum-dot molecules are created. In comparison, with GSMBE under As2 overpressure, as-grown QDs are transformed into quantum rings after partial capping with GaAs and then, after regrowth, become double QDs. At higher regrowth temperature, QD rings are formed. © 2007 American Institute of Physics.
62.
Jevasuwan, W; Panyakeow, S; Ratanathammaphan, S
In-droplet-induced formation of InP nanostructures by solid-source molecular-beam epitaxy Journal Article
In: Microelectronic Engineering, vol. 84, no. 5-8, pp. 1548-1551, 2007, ISSN: 01679317, (cited By 8).
@article{Jevasuwan2007a,
title = {In-droplet-induced formation of InP nanostructures by solid-source molecular-beam epitaxy},
author = {W Jevasuwan and S Panyakeow and S Ratanathammaphan},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34247626356&doi=10.1016%2fj.mee.2007.01.194&partnerID=40&md5=8ee0c6d8d5d0b484a44deb09461c57bb},
doi = {10.1016/j.mee.2007.01.194},
issn = {01679317},
year = {2007},
date = {2007-01-01},
journal = {Microelectronic Engineering},
volume = {84},
number = {5-8},
pages = {1548-1551},
abstract = {We have successfully obtained self-assembled InP nanostructures on In0.49Ga0.51P layers by solid-source molecular-beam epitaxy using droplet-epitaxy. The growth sequence is initiated by indium deposition which was intended to form indium droplets and followed by irradiating P2 beam to crystallize the indium droplets to InP. Dependence of the surface morphology on the indium thickness and on indium deposition rate was investigated. The nanostructure depends strongly on the indium thickness. It is observed that ring-shape nanostructure is formed when the indium thickness is 1.6 ML and the ring-shape quantum-dot molecule is formed when the indium thickness is thicker than 1.6 ML, with the crystallization under 4 × 10-6 Torr of P2 beam at 200 °C for 5 min. The density, height and ring-shape formation pattern of nanostructures also depend on the indium thickness and on the indium deposition rate. © 2007 Elsevier B.V. All rights reserved.},
note = {cited By 8},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We have successfully obtained self-assembled InP nanostructures on In0.49Ga0.51P layers by solid-source molecular-beam epitaxy using droplet-epitaxy. The growth sequence is initiated by indium deposition which was intended to form indium droplets and followed by irradiating P2 beam to crystallize the indium droplets to InP. Dependence of the surface morphology on the indium thickness and on indium deposition rate was investigated. The nanostructure depends strongly on the indium thickness. It is observed that ring-shape nanostructure is formed when the indium thickness is 1.6 ML and the ring-shape quantum-dot molecule is formed when the indium thickness is thicker than 1.6 ML, with the crystallization under 4 × 10-6 Torr of P2 beam at 200 °C for 5 min. The density, height and ring-shape formation pattern of nanostructures also depend on the indium thickness and on the indium deposition rate. © 2007 Elsevier B.V. All rights reserved.
63.
Suraprapapich, S; Shen, Y M; Odnoblyudov, V A; Fainman, Y; Panyakeow, S; Tu, C W
Self-assembled lateral Bi-quantum-dot molecule formation by gas-source molecular beam epitaxy Journal Article
In: Journal of Crystal Growth, vol. 301-302, no. SPEC. ISS., pp. 735-739, 2007, ISSN: 00220248, (cited By 19).
@article{Suraprapapich2007b,
title = {Self-assembled lateral Bi-quantum-dot molecule formation by gas-source molecular beam epitaxy},
author = {S Suraprapapich and Y M Shen and V A Odnoblyudov and Y Fainman and S Panyakeow and C W Tu},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947320929&doi=10.1016%2fj.jcrysgro.2006.11.120&partnerID=40&md5=1134e9952a47f2e0e4118c2b030376c8},
doi = {10.1016/j.jcrysgro.2006.11.120},
issn = {00220248},
year = {2007},
date = {2007-01-01},
journal = {Journal of Crystal Growth},
volume = {301-302},
number = {SPEC. ISS.},
pages = {735-739},
abstract = {Self-assembled InAs bi-quantum-dot molecules (BQDMs) on GaAs (0 0 1) have been achieved using gas-source molecular beam epitaxy (GSMBE) and characterized by atomic force microscopy (AFM) and photoluminescence (PL) measurements. After the initial InAs quantum dots are partially capped with GaAs and followed by deposition of InAs, BQDMs are formed. Photoluminescence spectra of BQDMs can be described by two Gaussian-fitted curves at low temperature due to two different dot sizes. This is consistent with dot height histograms obtained from AFM images of BQDMs. For PL intensity, thermal quenching is observed at temperatures above 100 K. The activation energy of BQDM PL corresponds to nonradiative recombination due to defected-related states and potential fluctuation. © 2006 Elsevier B.V. All rights reserved.},
note = {cited By 19},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Self-assembled InAs bi-quantum-dot molecules (BQDMs) on GaAs (0 0 1) have been achieved using gas-source molecular beam epitaxy (GSMBE) and characterized by atomic force microscopy (AFM) and photoluminescence (PL) measurements. After the initial InAs quantum dots are partially capped with GaAs and followed by deposition of InAs, BQDMs are formed. Photoluminescence spectra of BQDMs can be described by two Gaussian-fitted curves at low temperature due to two different dot sizes. This is consistent with dot height histograms obtained from AFM images of BQDMs. For PL intensity, thermal quenching is observed at temperatures above 100 K. The activation energy of BQDM PL corresponds to nonradiative recombination due to defected-related states and potential fluctuation. © 2006 Elsevier B.V. All rights reserved.
64.
Suraprapapich, S; Thainoi, S; Kanjanachuchai, S; Panyakeow, S
Thin-capping-and-regrowth molecular beam epitaxial technique for quantum dots and quantum-dot molecules Journal Article
In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, vol. 24, no. 3, pp. 1665-1667, 2006, ISSN: 10711023, (cited By 7).
@article{Suraprapapich2006a,
title = {Thin-capping-and-regrowth molecular beam epitaxial technique for quantum dots and quantum-dot molecules},
author = {S Suraprapapich and S Thainoi and S Kanjanachuchai and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33744825213&doi=10.1116%2f1.2190666&partnerID=40&md5=1e8c086a6988d4961ca97daa1b509848},
doi = {10.1116/1.2190666},
issn = {10711023},
year = {2006},
date = {2006-01-01},
journal = {Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures},
volume = {24},
number = {3},
pages = {1665-1667},
abstract = {A thin-capping-and-regrowth molecular beam epitaxial technique is proposed and demonstrated to be a suitable approach for the growth of lateral quantum-dot molecules (QDMs). By regrowing on top of nanoholes, previously formed from as-grown quantum dots (QDs) via a thin-capping process, nanopropeller QDs are formed. By repeating the thin-capping-and-regrowth process for several cycles at the regrown thickness of 0.6 ML, nanopropeller QDs are linked along the [1 1- 0] crystallographic direction, leading to the alignment of QDs. The thin-capping-and-regrowth process is repeated for 1, 3, 5, 7, and 10 cycles on different samples for comparison purposes. It is found from ex situ atomic force microscopy that at 7 cycles of thin capping and regrowth of QDs, the best alignment of QDs is achieved. This is due to the strain having an optimum condition. The samples that undergo three and five thin-capping-and-regrowth cycles show some randomness of QD formation. When the process is repeated for 10 cycles, QDs become randomly distributed, but with a higher dot density than the as-grown sample. The high dot density results in a strong photoluminescence at room temperature. It is also shown that when self-aligned QDs are used as templates, aligned QDMs can be obtained at a regrowth thickness of 1.2 ML. © 2006 American Vacuum Society.},
note = {cited By 7},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A thin-capping-and-regrowth molecular beam epitaxial technique is proposed and demonstrated to be a suitable approach for the growth of lateral quantum-dot molecules (QDMs). By regrowing on top of nanoholes, previously formed from as-grown quantum dots (QDs) via a thin-capping process, nanopropeller QDs are formed. By repeating the thin-capping-and-regrowth process for several cycles at the regrown thickness of 0.6 ML, nanopropeller QDs are linked along the [1 1- 0] crystallographic direction, leading to the alignment of QDs. The thin-capping-and-regrowth process is repeated for 1, 3, 5, 7, and 10 cycles on different samples for comparison purposes. It is found from ex situ atomic force microscopy that at 7 cycles of thin capping and regrowth of QDs, the best alignment of QDs is achieved. This is due to the strain having an optimum condition. The samples that undergo three and five thin-capping-and-regrowth cycles show some randomness of QD formation. When the process is repeated for 10 cycles, QDs become randomly distributed, but with a higher dot density than the as-grown sample. The high dot density results in a strong photoluminescence at room temperature. It is also shown that when self-aligned QDs are used as templates, aligned QDMs can be obtained at a regrowth thickness of 1.2 ML. © 2006 American Vacuum Society.
65.
Suraprapapich, S; Kanjanachuchai, S; Thainoi, S; Panyakeow, S
Self-assembled lateral InAs quantum dot molecules: Dot ensemble control and polarization-dependent photoluminescence Journal Article
In: Microelectronic Engineering, vol. 83, no. 4-9 SPEC. ISS., pp. 1526-1529, 2006, ISSN: 01679317, (cited By 4).
@article{Suraprapapich2006b,
title = {Self-assembled lateral InAs quantum dot molecules: Dot ensemble control and polarization-dependent photoluminescence},
author = {S Suraprapapich and S Kanjanachuchai and S Thainoi and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646059186&doi=10.1016%2fj.mee.2006.01.191&partnerID=40&md5=93bf6cc3f1387e7f7b53baaf6456b399},
doi = {10.1016/j.mee.2006.01.191},
issn = {01679317},
year = {2006},
date = {2006-01-01},
journal = {Microelectronic Engineering},
volume = {83},
number = {4-9 SPEC. ISS.},
pages = {1526-1529},
abstract = {By proper control of underlying templates, lateral InAs quantum dot molecules (QDMs) can be grown with a desired number of quantum dots (QDs) per molecule. We demonstrate that by capping as-grown InAs QDs with lattice-mismatched GaAs layer and by varying the capping temperature between 430 and 470 °C, we are able to control the span of nanoholes template to between 150 and 300 nm. InAs regrowth on this template result in nanopropellers (0.6 ML regrowth) or QDMs (1.2 ML), the latter with 4-12 QDs per molecule depending on the span of the underlying nanoholes template. All QDM samples grown share a characteristic feature with a clear preference to orient along the [ 1 over(1, ̄) 0 ] crystallographic direction. Room-temperature photoluminescence measurements show a strong polarization-dependent characteristic, in good agreements with the QDM's geometry. © 2006 Elsevier B.V. All rights reserved.},
note = {cited By 4},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
By proper control of underlying templates, lateral InAs quantum dot molecules (QDMs) can be grown with a desired number of quantum dots (QDs) per molecule. We demonstrate that by capping as-grown InAs QDs with lattice-mismatched GaAs layer and by varying the capping temperature between 430 and 470 °C, we are able to control the span of nanoholes template to between 150 and 300 nm. InAs regrowth on this template result in nanopropellers (0.6 ML regrowth) or QDMs (1.2 ML), the latter with 4-12 QDs per molecule depending on the span of the underlying nanoholes template. All QDM samples grown share a characteristic feature with a clear preference to orient along the [ 1 over(1, ̄) 0 ] crystallographic direction. Room-temperature photoluminescence measurements show a strong polarization-dependent characteristic, in good agreements with the QDM's geometry. © 2006 Elsevier B.V. All rights reserved.
66.
Suraprapapich, S; Kanjanachuchai, S; Thainoi, S; Panyakeow, S
Regrowth of self-assembled InAs quantum dots on nanohole and stripe templates Journal Article
In: Journal of Microlithography, Microfabrication and Microsystems, vol. 5, no. 1, 2006, ISSN: 15371646, (cited By 2).
@article{Suraprapapich2006,
title = {Regrowth of self-assembled InAs quantum dots on nanohole and stripe templates},
author = {S Suraprapapich and S Kanjanachuchai and S Thainoi and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748533461&doi=10.1117%2f1.2177287&partnerID=40&md5=2b92606f21b6c9d163f1dbe3468813ed},
doi = {10.1117/1.2177287},
issn = {15371646},
year = {2006},
date = {2006-01-01},
journal = {Journal of Microlithography, Microfabrication and Microsystems},
volume = {5},
number = {1},
abstract = {Self-assembled InAs quantum dots (QDs) are grown on two types of templates by molecular beam epitaxy (MBE). A nanohole template is prepared by first growing InAs QDs on a GaAs substrate by a standard MBE process, then capping the QDs with a thin latticemismatched layer of GaAs. Subsequent annealing of the nanohole template results in a stripe template. We are able to transfer the patterns of self-assembled QDs onto these two types of templates: regrowth on the nanohole template results in uniform QDs situated in the nanoholes, while regrowth on the stripe template results in chains of QDs aligned along the stripes. Our results imply that self-assembled QDs can be grown onto in-situ prepared patterned substrates, with limited degree of randomness. © 2006 Society of Photo-Optical Instrumentation Engineers.},
note = {cited By 2},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Self-assembled InAs quantum dots (QDs) are grown on two types of templates by molecular beam epitaxy (MBE). A nanohole template is prepared by first growing InAs QDs on a GaAs substrate by a standard MBE process, then capping the QDs with a thin latticemismatched layer of GaAs. Subsequent annealing of the nanohole template results in a stripe template. We are able to transfer the patterns of self-assembled QDs onto these two types of templates: regrowth on the nanohole template results in uniform QDs situated in the nanoholes, while regrowth on the stripe template results in chains of QDs aligned along the stripes. Our results imply that self-assembled QDs can be grown onto in-situ prepared patterned substrates, with limited degree of randomness. © 2006 Society of Photo-Optical Instrumentation Engineers.
67.
Thainoi, S; Suraprapapich, S; Sawadsaringkarn, M; Panyakeow, S
n-GaAlAs on p-GaAs heterostructure solar cells grown by molecular beam epitaxy Journal Article
In: Solar Energy Materials and Solar Cells, vol. 90, no. 18-19, pp. 2989-2994, 2006, ISSN: 09270248, (cited By 2).
@article{Thainoi2006,
title = {n-GaAlAs on p-GaAs heterostructure solar cells grown by molecular beam epitaxy},
author = {S Thainoi and S Suraprapapich and M Sawadsaringkarn and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748302821&doi=10.1016%2fj.solmat.2006.06.004&partnerID=40&md5=e6e5e2425e46de17aa96caced1d0c039},
doi = {10.1016/j.solmat.2006.06.004},
issn = {09270248},
year = {2006},
date = {2006-01-01},
journal = {Solar Energy Materials and Solar Cells},
volume = {90},
number = {18-19},
pages = {2989-2994},
abstract = {p-GaAs substrate was used as the starting material in molecular beam epitaxial growth. n-type GaAlAs for heterostructure and n-GaAs capping layer were then grown after a buffer layer deposition on the substrate. The n-GaAlAs on p-GaAs heterostructure solar cells, with active area of 13.25 mm2 under 100 mW/cm2 AM1 illumination light source, provide a typical output as follows: Voc=0.73 V},
note = {cited By 2},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
p-GaAs substrate was used as the starting material in molecular beam epitaxial growth. n-type GaAlAs for heterostructure and n-GaAs capping layer were then grown after a buffer layer deposition on the substrate. The n-GaAlAs on p-GaAs heterostructure solar cells, with active area of 13.25 mm2 under 100 mW/cm2 AM1 illumination light source, provide a typical output as follows: Voc=0.73 V
68.
Suraprapapich, S; Thainoi, S; Kanjanachuchai, S; Panyakeow, S
Self-assembled quantum-dot molecules by molecular-beam epitaxy Journal Article
In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, vol. 23, no. 3, pp. 1217-1220, 2005, ISSN: 10711023, (cited By 29).
@article{Suraprapapich2005,
title = {Self-assembled quantum-dot molecules by molecular-beam epitaxy},
author = {S Suraprapapich and S Thainoi and S Kanjanachuchai and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-28244483878&doi=10.1116%2f1.1894417&partnerID=40&md5=8fe76b60e2e035123aafd589b0ad3db9},
doi = {10.1116/1.1894417},
issn = {10711023},
year = {2005},
date = {2005-01-01},
journal = {Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures},
volume = {23},
number = {3},
pages = {1217-1220},
abstract = {Self-assembled InAs quantum-dot (QD) molecules having high dot density and aligned dot set structure, which is defined by nanotemplates, were realized by thin capping and regrowth technique in a molecular-beam epitaxy process. Thin capping of GaAs on InAs QDs leads to the creation of nanoholes having a camel-like nanostructure due to anisotropic strain fields along the [1 1- 0] crystallographic direction and anisotropic surface diffusion accompanying the QD collapse. Regrowth of InAs QDs on the nanohole templates initially results in the formation of QDs with good size uniformity in the middle of features with the shape of propeller blades. This takes place at the regrowth thickness of 0.6 monolayer (ML). The strain at propellers' edge starts to play its role, creating sets of quantum dots surrounding the initial and centered dots at the regrowth thickness of 1.2 ML. The elongated configuration of propellers' blades defines the pattern of QD sets having five to six dots on each side. The dot density of the QD molecules is 3× 1010 cm-2, one order of magnitude higher than that of initial dot density (2× 109 cm-2). © 2005 American Vacuum Society.},
note = {cited By 29},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Self-assembled InAs quantum-dot (QD) molecules having high dot density and aligned dot set structure, which is defined by nanotemplates, were realized by thin capping and regrowth technique in a molecular-beam epitaxy process. Thin capping of GaAs on InAs QDs leads to the creation of nanoholes having a camel-like nanostructure due to anisotropic strain fields along the [1 1- 0] crystallographic direction and anisotropic surface diffusion accompanying the QD collapse. Regrowth of InAs QDs on the nanohole templates initially results in the formation of QDs with good size uniformity in the middle of features with the shape of propeller blades. This takes place at the regrowth thickness of 0.6 monolayer (ML). The strain at propellers' edge starts to play its role, creating sets of quantum dots surrounding the initial and centered dots at the regrowth thickness of 1.2 ML. The elongated configuration of propellers' blades defines the pattern of QD sets having five to six dots on each side. The dot density of the QD molecules is 3× 1010 cm-2, one order of magnitude higher than that of initial dot density (2× 109 cm-2). © 2005 American Vacuum Society.
69.
Suraprapapich, S; Thainoi, S; Laliew, C; Kanjanachuchai, S; Panyakeow, S
Self-assembled indium-arsenide elongated nanostructure grown by molecular beam epitaxy Journal Article
In: International Journal of Nanoscience, vol. 4, no. 2, pp. 253-259, 2005, ISSN: 0219581X, (cited By 1).
@article{Suraprapapich2005a,
title = {Self-assembled indium-arsenide elongated nanostructure grown by molecular beam epitaxy},
author = {S Suraprapapich and S Thainoi and C Laliew and S Kanjanachuchai and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-21144447441&doi=10.1142%2fS0219581X05003012&partnerID=40&md5=44b39e3c368f0649732a53afa198e2a3},
doi = {10.1142/S0219581X05003012},
issn = {0219581X},
year = {2005},
date = {2005-01-01},
journal = {International Journal of Nanoscience},
volume = {4},
number = {2},
pages = {253-259},
abstract = {Self-assembled InAs elongated nanostructures were fabricated by continuous processing steps, starting from self-assembling of quantum dots, thin capping over the quantum dots to induce an anisotropic strain field, and to anneal the quantum dots in the molecular-beam-epitaxy machine. In-situ RHEED observations at each processing step were studied and confirmed by ex-situ AFM images of the surface morphology. The elongated nanostructures were demonstrated to be templates for chains of uniform quantum dots. © World Scientific Publishing Company.},
note = {cited By 1},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Self-assembled InAs elongated nanostructures were fabricated by continuous processing steps, starting from self-assembling of quantum dots, thin capping over the quantum dots to induce an anisotropic strain field, and to anneal the quantum dots in the molecular-beam-epitaxy machine. In-situ RHEED observations at each processing step were studied and confirmed by ex-situ AFM images of the surface morphology. The elongated nanostructures were demonstrated to be templates for chains of uniform quantum dots. © World Scientific Publishing Company.
70.
Suraprapapich, S; Kanjanachuchai, S; Thainoi, S; Panyakeow, S
Ordered quantum dots formation on engineered template by molecular beam epitaxy Journal Article
In: Microelectronic Engineering, vol. 78-79, no. 1-4, pp. 349-352, 2005, ISSN: 01679317, (cited By 4; Conference of Proceedings of the 30th International Conference on Micro- and Nano-Engineering ; Conference Date: 19 September 2004 Through 22 September 2004; Conference Code:64391).
@article{Suraprapapich2005b,
title = {Ordered quantum dots formation on engineered template by molecular beam epitaxy},
author = {S Suraprapapich and S Kanjanachuchai and S Thainoi and S Panyakeow},
editor = {Drift E W J M Kruit P.},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-14944358228&doi=10.1016%2fj.mee.2004.12.046&partnerID=40&md5=97bb89cadd385de23809b74aaab4a48c},
doi = {10.1016/j.mee.2004.12.046},
issn = {01679317},
year = {2005},
date = {2005-01-01},
journal = {Microelectronic Engineering},
volume = {78-79},
number = {1-4},
pages = {349-352},
abstract = {We have achieved partial ordering of InAs quantum dots (QDs) grown on a flat GaAs (0 0 1) substrate. Although the growth of the first QD layer results in random distribution of QDs, subsequent processes that involve multiple cycles of capping, regrowth and annealing have turned the flat substrate into a template with stripes in the [11̄0] direction. Regrowth on the engineered template results in chains of relatively uniform InAs QDs connected in series. © 2005 Elsevier B.V. All rights reserved.},
note = {cited By 4; Conference of Proceedings of the 30th International Conference on Micro- and Nano-Engineering ; Conference Date: 19 September 2004 Through 22 September 2004; Conference Code:64391},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We have achieved partial ordering of InAs quantum dots (QDs) grown on a flat GaAs (0 0 1) substrate. Although the growth of the first QD layer results in random distribution of QDs, subsequent processes that involve multiple cycles of capping, regrowth and annealing have turned the flat substrate into a template with stripes in the [11̄0] direction. Regrowth on the engineered template results in chains of relatively uniform InAs QDs connected in series. © 2005 Elsevier B.V. All rights reserved.
71.
Kiravittaya, S; Songmuang, R; Jin-Phillipp, N Y; Panyakeow, S; Schmidt, O G
Self-assembled nanoholes and lateral QD bi-molecules by molecular beam epitaxy and atomically precise in situ etching Journal Article
In: Journal of Crystal Growth, vol. 251, no. 1-4, pp. 258-263, 2003, ISSN: 00220248, (cited By 28; Conference of Proceedings of the Molecular Beam Epitaxy 2002 ; Conference Date: 15 September 2002 Through 20 September 2002; Conference Code:60890).
@article{Kiravittaya2003,
title = {Self-assembled nanoholes and lateral QD bi-molecules by molecular beam epitaxy and atomically precise in situ etching},
author = {S Kiravittaya and R Songmuang and N Y Jin-Phillipp and S Panyakeow and O G Schmidt},
editor = {Tu C W Harris J.S. Miller D.L.},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037380594&doi=10.1016%2fS0022-0248%2802%2902475-2&partnerID=40&md5=7244fb8e45d78f5beb5835a2663f88c6},
doi = {10.1016/S0022-0248(02)02475-2},
issn = {00220248},
year = {2003},
date = {2003-01-01},
journal = {Journal of Crystal Growth},
volume = {251},
number = {1-4},
pages = {258-263},
address = {San Francisco, CA},
abstract = {We present a systematic study of nanoholes formation on top of capped InAs quantum dots (QDs) by using AsBr3 in situ etching. The etching process can be divided into two regimes depending on the nominal etching depth and the thickness of the GaAs cap layer. In the first regime, 6-nm deep and 50-nm wide nanoholes are formed, which we ascribe to a strain selectivity of the etchant. Further supply of the etching gas causes the hole diameter to increase, while the depth stays approximately constant. Photoluminescence (PL) was used to confirm the removal of the buried InAs QDs during etching. The holes can be overgrown with InAs such that an atomically flat surface is recovered. Further InAs deposited on the filled-hole layer forms into pairs of self-assembled QDs - so-called lateral QD bi-molecules. These QD bi-molecules show narrow and intense PL signal at room temperature. © 2003 Elsevier Science B.V. All rights reserved.},
note = {cited By 28; Conference of Proceedings of the Molecular Beam Epitaxy 2002 ; Conference Date: 15 September 2002 Through 20 September 2002; Conference Code:60890},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present a systematic study of nanoholes formation on top of capped InAs quantum dots (QDs) by using AsBr3 in situ etching. The etching process can be divided into two regimes depending on the nominal etching depth and the thickness of the GaAs cap layer. In the first regime, 6-nm deep and 50-nm wide nanoholes are formed, which we ascribe to a strain selectivity of the etchant. Further supply of the etching gas causes the hole diameter to increase, while the depth stays approximately constant. Photoluminescence (PL) was used to confirm the removal of the buried InAs QDs during etching. The holes can be overgrown with InAs such that an atomically flat surface is recovered. Further InAs deposited on the filled-hole layer forms into pairs of self-assembled QDs - so-called lateral QD bi-molecules. These QD bi-molecules show narrow and intense PL signal at room temperature. © 2003 Elsevier Science B.V. All rights reserved.
72.
Songmuang, R; Kiravittaya, S; Sawadsaringkarn, M; Panyakeow, S; Schmidt, O G
Photoluminescence investigation of low-temperature capped self-assembled InAs/GaAs quantum dots Journal Article
In: Journal of Crystal Growth, vol. 251, no. 1-4, pp. 166-171, 2003, ISSN: 00220248, (cited By 33; Conference of Proceedings of the Molecular Beam Epitaxy 2002 ; Conference Date: 15 September 2002 Through 20 September 2002; Conference Code:60890).
@article{Songmuang2003,
title = {Photoluminescence investigation of low-temperature capped self-assembled InAs/GaAs quantum dots},
author = {R Songmuang and S Kiravittaya and M Sawadsaringkarn and S Panyakeow and O G Schmidt},
editor = {Tu C W Harris J.S. Miller D.L.},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037380527&doi=10.1016%2fS0022-0248%2802%2902474-0&partnerID=40&md5=178de30fa2b93d18df97fd2184374680},
doi = {10.1016/S0022-0248(02)02474-0},
issn = {00220248},
year = {2003},
date = {2003-01-01},
journal = {Journal of Crystal Growth},
volume = {251},
number = {1-4},
pages = {166-171},
address = {San Francisco, CA},
abstract = {We use photoluminescence (PL) to compare large low-density and small high-density self-assembled InAs/GaAs quantum dots (QDs) - capped at low and high temperatures. The low-temperature capped QDs show an improved PL linewidth of 23-26meV, which is caused by an improvement of size and composition homogeneity of buried QDs due to suppressed material intermixing. The improvement is more pronounced for the small QDs. Excitation power and temperature-dependent PL are performed for all different QD types. © 2003 Elsevier Science B.V. All rights reserved.},
note = {cited By 33; Conference of Proceedings of the Molecular Beam Epitaxy 2002 ; Conference Date: 15 September 2002 Through 20 September 2002; Conference Code:60890},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We use photoluminescence (PL) to compare large low-density and small high-density self-assembled InAs/GaAs quantum dots (QDs) - capped at low and high temperatures. The low-temperature capped QDs show an improved PL linewidth of 23-26meV, which is caused by an improvement of size and composition homogeneity of buried QDs due to suppressed material intermixing. The improvement is more pronounced for the small QDs. Excitation power and temperature-dependent PL are performed for all different QD types. © 2003 Elsevier Science B.V. All rights reserved.
73.
Kiravittaya, S; Songmuang, R; Changmuang, P; Sopitpan, S; Ratanathammaphan, S; Sawadsaringkarn, M; Panyakeow, S
InAs/GaAs self-organized quantum dots on (4 1 1)A GaAs by molecular beam epitaxy Journal Article
In: Journal of Crystal Growth, vol. 227-228, pp. 1010-1015, 2001, ISSN: 00220248, (cited By 13; Conference of 11th International Conference on Molecular Beam Epitaxy ; Conference Date: 11 September 2000 Through 15 September 2000; Conference Code:58293).
@article{Kiravittaya2001,
title = {InAs/GaAs self-organized quantum dots on (4 1 1)A GaAs by molecular beam epitaxy},
author = {S Kiravittaya and R Songmuang and P Changmuang and S Sopitpan and S Ratanathammaphan and M Sawadsaringkarn and S Panyakeow},
editor = {Tu C W Kong M.},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035398657&doi=10.1016%2fS0022-0248%2801%2900978-2&partnerID=40&md5=a7aa51d7eedc1ce9b5de916f1d360468},
doi = {10.1016/S0022-0248(01)00978-2},
issn = {00220248},
year = {2001},
date = {2001-01-01},
journal = {Journal of Crystal Growth},
volume = {227-228},
pages = {1010-1015},
address = {Bijing},
abstract = {Self-organized InAs QDs formation on (4 1 1)A GaAs and on controlled (1 0 0) GaAs substrates were studied by in-situ RHEED observation, AFM measurement and PL spectroscopy. The transition from two-dimensional to three-dimensional growth on (4 1 1)A was observed by RHEED pattern transformation to indicate the critical layer thickness of InAs QDs formation. The result is almost the same as that on (1 0 0). Improvement of QDs alignment having dot size uniformity on (4 1 1)A was observed by AFM measurement. Enhanced optical properties of QDs on (4 1 1)A was shown by low-temperature PL spectroscopy. Strong PL peak at 966 nm having FWHM of 35 nm was obtained from the 3-stacked QDs on (4 1 1)A. The narrower PL FWHM of QDs peak on (4 1 1)A comes from the improved uniformity of QDs on (4 1 1)A. © 2001 Elsevier Science B.V.},
note = {cited By 13; Conference of 11th International Conference on Molecular Beam Epitaxy ; Conference Date: 11 September 2000 Through 15 September 2000; Conference Code:58293},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Self-organized InAs QDs formation on (4 1 1)A GaAs and on controlled (1 0 0) GaAs substrates were studied by in-situ RHEED observation, AFM measurement and PL spectroscopy. The transition from two-dimensional to three-dimensional growth on (4 1 1)A was observed by RHEED pattern transformation to indicate the critical layer thickness of InAs QDs formation. The result is almost the same as that on (1 0 0). Improvement of QDs alignment having dot size uniformity on (4 1 1)A was observed by AFM measurement. Enhanced optical properties of QDs on (4 1 1)A was shown by low-temperature PL spectroscopy. Strong PL peak at 966 nm having FWHM of 35 nm was obtained from the 3-stacked QDs on (4 1 1)A. The narrower PL FWHM of QDs peak on (4 1 1)A comes from the improved uniformity of QDs on (4 1 1)A. © 2001 Elsevier Science B.V.
74.
Sopitpan, S; Changmuang, P; Panyakeow, S
Monitoring and data analysis of a PV system connected to a grid for home applications Journal Article
In: Solar Energy Materials and Solar Cells, vol. 67, no. 1-4, pp. 481-490, 2001, ISSN: 09270248, (cited By 13).
@article{Sopitpan2001,
title = {Monitoring and data analysis of a PV system connected to a grid for home applications},
author = {S Sopitpan and P Changmuang and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035284227&doi=10.1016%2fS0927-0248%2800%2900317-2&partnerID=40&md5=0af873ca57d3eed0985c3703e02015a4},
doi = {10.1016/S0927-0248(00)00317-2},
issn = {09270248},
year = {2001},
date = {2001-01-01},
journal = {Solar Energy Materials and Solar Cells},
volume = {67},
number = {1-4},
pages = {481-490},
abstract = {Monitoring of a PV system connected to a grid was conducted to collect the system performance and compared to a PV stand-alone system. Daily solar inputs and load outputs for home applications of the two systems were recorded. Balance and surplus of energy in the systems were observed during dry and summer seasons when high solar radiation was recorded. During the raining season, with thunderstorms, solar radiation was low and grid cut-off occasionally occurred. Consequently, energy deficiencies and grid back-up of the systems were observed. It was found that the battery size of the PV system connected to the grid was reduced by a factor of 0.5-0.7 compared to the PV stand-alone counterpart for similar load behaviors. The merits of the PV system connected to the grid during grid cut-off was confirmed; the system proved to be appropriate for tropical countries where unstable electricity supply from the grid can occur during monsoon season.},
note = {cited By 13},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Monitoring of a PV system connected to a grid was conducted to collect the system performance and compared to a PV stand-alone system. Daily solar inputs and load outputs for home applications of the two systems were recorded. Balance and surplus of energy in the systems were observed during dry and summer seasons when high solar radiation was recorded. During the raining season, with thunderstorms, solar radiation was low and grid cut-off occasionally occurred. Consequently, energy deficiencies and grid back-up of the systems were observed. It was found that the battery size of the PV system connected to the grid was reduced by a factor of 0.5-0.7 compared to the PV stand-alone counterpart for similar load behaviors. The merits of the PV system connected to the grid during grid cut-off was confirmed; the system proved to be appropriate for tropical countries where unstable electricity supply from the grid can occur during monsoon season.
75.
Kiravittaya, S; Manmontri, U; Sopitpan, S; Ratanathammaphan, S; Antarasen, C; Sawadsaringkarn, M; Panyakeow, S
AlGaAs/GaAs/InGaAs composite MQW structures for photovoltaic applications Journal Article
In: Solar Energy Materials and Solar Cells, vol. 68, no. 1, pp. 89-95, 2001, ISSN: 09270248, (cited By 10).
@article{Kiravittaya2001a,
title = {AlGaAs/GaAs/InGaAs composite MQW structures for photovoltaic applications},
author = {S Kiravittaya and U Manmontri and S Sopitpan and S Ratanathammaphan and C Antarasen and M Sawadsaringkarn and S Panyakeow},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034826290&doi=10.1016%2fS0927-0248%2800%2900347-0&partnerID=40&md5=0b91108643e1322805ad48e2eb71af19},
doi = {10.1016/S0927-0248(00)00347-0},
issn = {09270248},
year = {2001},
date = {2001-01-01},
journal = {Solar Energy Materials and Solar Cells},
volume = {68},
number = {1},
pages = {89-95},
abstract = {AlGaAs/GaAs/InGaAs composite MQW structures were theoretically studied and simulated. The computer simulation indicated that an appropriate composite MQW, both with symmetrical and non-symmetrical structures, could keep |ψ|2 of quantized carriers at proper locations in electric-field-tilted quantum wells, so the efficient transition by photon absorption would be possible and applicable for photovoltaic cells which have the composite MQW as the active region. The AlGaAs/GaAs MQW and GaAs/InGaAs (4x) SQW structures were separately prepared by MBE and were evaluated for their spectral responses. The AlGaAs/GaAs MQW has a high response at a short wavelengths (peak at 685 nm) due to the quantized states in GaAs wells, while the GaAs/InGaAs SQW has a broader spectral response covering longer wavelengths (600-850 nm) because of the strong absorption in the GaAs barrier and substrate. However, (4x) photoluminescence peaks at 900-1100 nm that were found from GaAs/InGaAs strained quantum wells at room temperature are promising evidence for the longer wavelength spectral response. The AlGaAs/GaAs/InGaAs composite SQW and MQW samples were experimentally prepared by MBE techniques and tested for their optical properties. The broader photoluminescence peak was observed and reflected the nature of the composite structure. The study on the photospectral response of composite MQW structures has been conducted which provides the basic information for high performance solar cell design.},
note = {cited By 10},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
AlGaAs/GaAs/InGaAs composite MQW structures were theoretically studied and simulated. The computer simulation indicated that an appropriate composite MQW, both with symmetrical and non-symmetrical structures, could keep |ψ|2 of quantized carriers at proper locations in electric-field-tilted quantum wells, so the efficient transition by photon absorption would be possible and applicable for photovoltaic cells which have the composite MQW as the active region. The AlGaAs/GaAs MQW and GaAs/InGaAs (4x) SQW structures were separately prepared by MBE and were evaluated for their spectral responses. The AlGaAs/GaAs MQW has a high response at a short wavelengths (peak at 685 nm) due to the quantized states in GaAs wells, while the GaAs/InGaAs SQW has a broader spectral response covering longer wavelengths (600-850 nm) because of the strong absorption in the GaAs barrier and substrate. However, (4x) photoluminescence peaks at 900-1100 nm that were found from GaAs/InGaAs strained quantum wells at room temperature are promising evidence for the longer wavelength spectral response. The AlGaAs/GaAs/InGaAs composite SQW and MQW samples were experimentally prepared by MBE techniques and tested for their optical properties. The broader photoluminescence peak was observed and reflected the nature of the composite structure. The study on the photospectral response of composite MQW structures has been conducted which provides the basic information for high performance solar cell design.