S. Sopitpan - Academia.edu (original) (raw)

Papers by S. Sopitpan

Advanced Materials Research, 2010

Local structures of indium oxynitride (InON) nano-crystal prepared by reactive gas-timing RF magn... more Local structures of indium oxynitride (InON) nano-crystal prepared by reactive gas-timing RF magnetron sputtering technique are under investigation. Since the optical properties of these InON thin films depend on gas-timing ratio, the local structure analysis is needed in order to determine the relation between the gas timing ratio and its optical properties. In this work, InON thinfilm with 30:0 seconds (N2:O2) gas-timings ratio was analyzed for its local structure using X-ray absorption fine structure (XAFS) technique in conjunction with first principle calculation. The results indicate that the crystal structure of the film is wurtzite structure which is a typical structure of InN. However from the results of Auger Electron Spectroscopy (AES), there are oxygen contents in the film. Since XAFS analysis confirmed the 4-fold local structure of Indium atom, these oxygen atoms must be substituted in nitrogen sites with slightly changing the local structure of Indium atom. The best fit...

Journal of Crystal Growth

Journal of Crystal Growth

Journal of Crystal Growth

X-Ray Spectrometry, 2012

ABSTRACT Local structure of indium oxynitride thin films grown on silicon substrates was investig... more ABSTRACT Local structure of indium oxynitride thin films grown on silicon substrates was investigated by X‐ray absorption fine structure technique incorporated with first principle calculations. The thin films were grown by using reactive gas timing radio frequency (RF) magnetron sputtering technique with nitrogen (N2) and oxygen (O2) as reactive gasses. The reactive gasses were interchangeably fed into sputtering system at five different time intervals. The gas feeding time intervals of N2:O2 are 30 : 0, 30 : 5, 30 : 10, 30 : 20 and 10 : 30 s, respectively. The analysis results can be divided into three main categories. Firstly, the films grown with 30 : 0 and 30 : 5 s gas feeding time intervals are wurtzite structure indium nitride with 25 and 43% oxygen contaminations, respectively. Secondary, the film grown with 10 : 30 s gas feeding time intervals is bixbyite structure indium oxide. Finally, the films are alloying between indium nitride and indium oxide for other growth condition. The fitted radial distribution spectra, the structural parameters and the combination ratios of the alloys are discussed. Copyright © 2012 John Wiley & Sons, Ltd.

International Conference on Experimental Mechanics 2013 and Twelfth Asian Conference on Experimental Mechanics, 2014

Solar Energy Materials and Solar Cells, 2001

Monitoring of a PV system connected to a grid was conducted to collect the system performance and... more 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-o! occasionally occurred. Consequently, energy de"ciencies 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-o! was con"rmed; the system proved to be appropriate for tropical countries where unstable electricity supply from the grid can occur during monsoon season.

2008 5th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, 2008

ABSTRACT This paper describes the impact of thickness of cobalt silicide to the sentivity of p-n ... more ABSTRACT This paper describes the impact of thickness of cobalt silicide to the sentivity of p-n junction temperature sensor. The starting cobalt thickness of 12, 20 and 30 nm and non-silicided reference wafer have been used. The maximum sentivity for starting cobalt thickness of 12 nm has been obtained from both large area and long perimeter p-n junction. This corresponds to the low leakage current and series resistance.

Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036), 2000

Three different configurations of PV systems, i.e. PV stand-alone, PV direct and PV connected to ... more Three different configurations of PV systems, i.e. PV stand-alone, PV direct and PV connected to a grid, were set up and studied at a house in Bangkok. The results were compared to the grid-connected PV systems at other pilot project houses installed by the Electricity Generating Authority of Thailand. The three systems w e r e f o u n d t o o u t p e r f o r m t h e c o n v e n t i o n a l grid-connected PV system in many aspects.

1999 ISES Solar World Congress, 2000

2010 3rd International Nanoelectronics Conference (INEC), 2010

Local structure of indium oxynitride thin films grown on silicon substrates was investigated by X... more Local structure of indium oxynitride thin films grown on silicon substrates was investigated by X-ray absorption fine structure technique incorporated with first principle calculations. The thin films were grown by using reactive gas timing radio frequency (RF) magnetron sputtering technique with nitrogen (N 2 ) and oxygen (O 2 ) as reactive gasses. The reactive gasses were interchangeably fed into sputtering system at five different time intervals. The gas feeding time intervals of N 2 :O 2 are 30 : 0, 30 : 5, 30 : 10, 30 : 20 and 10 : 30 s, respectively. The analysis results can be divided into three main categories. Firstly, the films grown with 30 : 0 and 30 : 5 s gas feeding time intervals are wurtzite structure indium nitride with 25 and 43% oxygen contaminations, respectively. Secondary, the film grown with 10 : 30 s gas feeding time intervals is bixbyite structure indium oxide. Finally, the films are alloying between indium nitride and indium oxide for other growth condition. The fitted radial distribution spectra, the structural parameters and the combination ratios of the alloys are discussed.

Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036), 2000

GaAs/AlGaAs and InGaAs/GaAs multquantum well (MQW) structures were fabricated by Molecular Beam E... more GaAs/AlGaAs and InGaAs/GaAs multquantum well (MQW) structures were fabricated by Molecular Beam Epitaxy (MBE) technique. Spectral response of these two quantum structures were investigated by photocurrent measurements. The response peak of the GaAs/ AlGaAs MQW is at 684 om and InGaAs/GaAs MQW exhibits responses maxima in 700-800 om spectral regions. The absorption of these two MQW structures depend on their multiplication of the same quantum well width.

Solar Energy Materials and Solar Cells, 2001

AlGaAs/GaAs/InGaAs composite MQW structures were theoretically studied and simulated. The compute... more 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 " " of quantized carriers at proper locations in electric-"eld-tilted quantum wells, so the e$cient 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 werefound 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 re#ected 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.

Solar Energy Materials and Solar Cells, 1998

ABSTRACT GaAs/GaAlAs MQW structures with varying well widths having narrowest wells on the top la... more ABSTRACT GaAs/GaAlAs MQW structures with varying well widths having narrowest wells on the top layers and gradually wider wells for the inner layers were studied and confirmed by Auger spectroscopy and photoluminescence measurements. Multiplication of quantum wells gives stronger photoluminescence due to higher density of quantized states in the structure. This MQW structure was experimented in the photoconductivity and photocurrent measurements at room temperature. It is found that at low multiplication of quantum wells in MQW structure, the photoconductivity effect was mainly controlled by bulk material as shown in the spectral response. Photocurrent at low bias voltage shows relatively better spectral sensitivity at shorter wavelength. The photoconductivity and photocurrent measurements indicate that appropriate MQW structures acting as broader absorbers due to graded characters of quantized energy states are needed for photovoltaic application. Integration of MQW structure to solar cell structure was also investigated.

Materials Science in Semiconductor Processing, 2008

This paper presents the method to prepare and characterize high-dielectric constant aluminum oxyn... more This paper presents the method to prepare and characterize high-dielectric constant aluminum oxynitride (AlON) formed by RF gas-timing sputtering. AlON layers of 725 nm have been prepared on metal-dielectric-metal structure with substrate temperature below 100 1C. Capacitance versus bias voltage has been measured. The dielectric constant of AlON has been calculated from the slope of the plot of capacitance versus capacitor area. The value of 11 has been obtained from this study. This depends on the composition of the AlON material, which is analyzed by Auger electron spectroscopy.

Journal of Crystal Growth, 2014

ABSTRACT We perform structural and optical investigations of GaSb/GaAs quantum dots (QDs) grown o... more ABSTRACT We perform structural and optical investigations of GaSb/GaAs quantum dots (QDs) grown on Ge (001) substrates by molecular beam epitaxy. Anti-phase domains (APDs) of GaAs are distributed on Ge substrate after the growth of GaAs due to the growth nature of III–V compound on group IV semiconductors having polar and non-polar behaviors. The APDs affect the QD growth as demonstrated by the growth of conventional InAs QDs on this surface. For GaSb QDs, the GaSb layer is grown on GaAs APD surface and compared with the GaSb layer on conventional (001) GaAs surface. Self-assembled QDs are formed on both surfaces but structural analysis reveals evidence of shape and size differences, which is attributed to the influence of the initial surface. Photoluminescence of GaSb/GaAs QDs grown on both Ge and GaAs substrates is studied. Emission from GaSb/GaAs QDs on Ge substrate can be detected till near room temperature (270 K).

Journal of Crystal Growth, 1997

Lines of local epitaxy of GaAsGaAlAs multiple quantum wells with linewidth of 7 and 5 μm having l... more Lines of local epitaxy of GaAsGaAlAs multiple quantum wells with linewidth of 7 and 5 μm having line separation of 250 μm were fabricated by molecular beam epitaxy (MBE) using shadow masking technique. Photoluminescence (PL) measurements at 10 K were performed by using an argon laser with cylindrical lens producing line focus and with circular lens producing point focus for the excitation. The focussed line and focussed point of laser beam were ∼ 100 μm and could be aligned to the stripes of MQW. The PL spectrum characteristics reflect the quantum well structure as well as the crystal quality of shadow masked epitaxy layers. The PL spectrum shows double PL peaks at 758 and 774 nm with nearly equal intensity when the exciting beam lined parallel to the stripes of MQW have a 7 μm window and quantum well width of 30 monolayers. Overlapping PL peaks at 810 and 818 nm were observed from MQW having 5 μm window and quantum well width of 60 monolayers. Similar results were obtained by point focussed laser beam and by line focussed laser beam at perpendicular configuration. A stronger PL peak at 818 nm was clearly emphasized by strip-off MQW samples having 5 μm stripes. The PL peak from a shadow masked MQW sample was sharp having spectral FWHM of 14 nm and was relatively stronger than that obtained from conventional MQW samples. These experimental data indicated that MBE grown MQW mesa using shadow masking technique is suitable for quantum device fabrication.

Journal of Crystal Growth, 2001

Self-organized InAs QDs formation on (4 1 1)A GaAs and on controlled (1 0 0) GaAs substrates were... more Self-organized InAs QDs formation on (4 1 1)A GaAs and on controlled (1 0 0) GaAs substrates were studied by insitu RHEED observation, AFM measurement and PL spectroscopy. The transition from two-dimensional to threedimensional 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 3stacked 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 (411)A. #

Advanced Materials Research, 2010

Local structures of indium oxynitride (InON) nano-crystal prepared by reactive gas-timing RF magn... more Local structures of indium oxynitride (InON) nano-crystal prepared by reactive gas-timing RF magnetron sputtering technique are under investigation. Since the optical properties of these InON thin films depend on gas-timing ratio, the local structure analysis is needed in order to determine the relation between the gas timing ratio and its optical properties. In this work, InON thinfilm with 30:0 seconds (N2:O2) gas-timings ratio was analyzed for its local structure using X-ray absorption fine structure (XAFS) technique in conjunction with first principle calculation. The results indicate that the crystal structure of the film is wurtzite structure which is a typical structure of InN. However from the results of Auger Electron Spectroscopy (AES), there are oxygen contents in the film. Since XAFS analysis confirmed the 4-fold local structure of Indium atom, these oxygen atoms must be substituted in nitrogen sites with slightly changing the local structure of Indium atom. The best fit...

Journal of Crystal Growth

Journal of Crystal Growth

Journal of Crystal Growth

X-Ray Spectrometry, 2012

ABSTRACT Local structure of indium oxynitride thin films grown on silicon substrates was investig... more ABSTRACT Local structure of indium oxynitride thin films grown on silicon substrates was investigated by X‐ray absorption fine structure technique incorporated with first principle calculations. The thin films were grown by using reactive gas timing radio frequency (RF) magnetron sputtering technique with nitrogen (N2) and oxygen (O2) as reactive gasses. The reactive gasses were interchangeably fed into sputtering system at five different time intervals. The gas feeding time intervals of N2:O2 are 30 : 0, 30 : 5, 30 : 10, 30 : 20 and 10 : 30 s, respectively. The analysis results can be divided into three main categories. Firstly, the films grown with 30 : 0 and 30 : 5 s gas feeding time intervals are wurtzite structure indium nitride with 25 and 43% oxygen contaminations, respectively. Secondary, the film grown with 10 : 30 s gas feeding time intervals is bixbyite structure indium oxide. Finally, the films are alloying between indium nitride and indium oxide for other growth condition. The fitted radial distribution spectra, the structural parameters and the combination ratios of the alloys are discussed. Copyright © 2012 John Wiley & Sons, Ltd.

International Conference on Experimental Mechanics 2013 and Twelfth Asian Conference on Experimental Mechanics, 2014

Solar Energy Materials and Solar Cells, 2001

Monitoring of a PV system connected to a grid was conducted to collect the system performance and... more 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-o! occasionally occurred. Consequently, energy de"ciencies 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-o! was con"rmed; the system proved to be appropriate for tropical countries where unstable electricity supply from the grid can occur during monsoon season.

2008 5th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, 2008

ABSTRACT This paper describes the impact of thickness of cobalt silicide to the sentivity of p-n ... more ABSTRACT This paper describes the impact of thickness of cobalt silicide to the sentivity of p-n junction temperature sensor. The starting cobalt thickness of 12, 20 and 30 nm and non-silicided reference wafer have been used. The maximum sentivity for starting cobalt thickness of 12 nm has been obtained from both large area and long perimeter p-n junction. This corresponds to the low leakage current and series resistance.

Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036), 2000

Three different configurations of PV systems, i.e. PV stand-alone, PV direct and PV connected to ... more Three different configurations of PV systems, i.e. PV stand-alone, PV direct and PV connected to a grid, were set up and studied at a house in Bangkok. The results were compared to the grid-connected PV systems at other pilot project houses installed by the Electricity Generating Authority of Thailand. The three systems w e r e f o u n d t o o u t p e r f o r m t h e c o n v e n t i o n a l grid-connected PV system in many aspects.

1999 ISES Solar World Congress, 2000

2010 3rd International Nanoelectronics Conference (INEC), 2010

Local structure of indium oxynitride thin films grown on silicon substrates was investigated by X... more Local structure of indium oxynitride thin films grown on silicon substrates was investigated by X-ray absorption fine structure technique incorporated with first principle calculations. The thin films were grown by using reactive gas timing radio frequency (RF) magnetron sputtering technique with nitrogen (N 2 ) and oxygen (O 2 ) as reactive gasses. The reactive gasses were interchangeably fed into sputtering system at five different time intervals. The gas feeding time intervals of N 2 :O 2 are 30 : 0, 30 : 5, 30 : 10, 30 : 20 and 10 : 30 s, respectively. The analysis results can be divided into three main categories. Firstly, the films grown with 30 : 0 and 30 : 5 s gas feeding time intervals are wurtzite structure indium nitride with 25 and 43% oxygen contaminations, respectively. Secondary, the film grown with 10 : 30 s gas feeding time intervals is bixbyite structure indium oxide. Finally, the films are alloying between indium nitride and indium oxide for other growth condition. The fitted radial distribution spectra, the structural parameters and the combination ratios of the alloys are discussed.

Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036), 2000

GaAs/AlGaAs and InGaAs/GaAs multquantum well (MQW) structures were fabricated by Molecular Beam E... more GaAs/AlGaAs and InGaAs/GaAs multquantum well (MQW) structures were fabricated by Molecular Beam Epitaxy (MBE) technique. Spectral response of these two quantum structures were investigated by photocurrent measurements. The response peak of the GaAs/ AlGaAs MQW is at 684 om and InGaAs/GaAs MQW exhibits responses maxima in 700-800 om spectral regions. The absorption of these two MQW structures depend on their multiplication of the same quantum well width.

Solar Energy Materials and Solar Cells, 2001

AlGaAs/GaAs/InGaAs composite MQW structures were theoretically studied and simulated. The compute... more 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 " " of quantized carriers at proper locations in electric-"eld-tilted quantum wells, so the e$cient 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 werefound 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 re#ected 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.

Solar Energy Materials and Solar Cells, 1998

ABSTRACT GaAs/GaAlAs MQW structures with varying well widths having narrowest wells on the top la... more ABSTRACT GaAs/GaAlAs MQW structures with varying well widths having narrowest wells on the top layers and gradually wider wells for the inner layers were studied and confirmed by Auger spectroscopy and photoluminescence measurements. Multiplication of quantum wells gives stronger photoluminescence due to higher density of quantized states in the structure. This MQW structure was experimented in the photoconductivity and photocurrent measurements at room temperature. It is found that at low multiplication of quantum wells in MQW structure, the photoconductivity effect was mainly controlled by bulk material as shown in the spectral response. Photocurrent at low bias voltage shows relatively better spectral sensitivity at shorter wavelength. The photoconductivity and photocurrent measurements indicate that appropriate MQW structures acting as broader absorbers due to graded characters of quantized energy states are needed for photovoltaic application. Integration of MQW structure to solar cell structure was also investigated.

Materials Science in Semiconductor Processing, 2008

This paper presents the method to prepare and characterize high-dielectric constant aluminum oxyn... more This paper presents the method to prepare and characterize high-dielectric constant aluminum oxynitride (AlON) formed by RF gas-timing sputtering. AlON layers of 725 nm have been prepared on metal-dielectric-metal structure with substrate temperature below 100 1C. Capacitance versus bias voltage has been measured. The dielectric constant of AlON has been calculated from the slope of the plot of capacitance versus capacitor area. The value of 11 has been obtained from this study. This depends on the composition of the AlON material, which is analyzed by Auger electron spectroscopy.

Journal of Crystal Growth, 2014

ABSTRACT We perform structural and optical investigations of GaSb/GaAs quantum dots (QDs) grown o... more ABSTRACT We perform structural and optical investigations of GaSb/GaAs quantum dots (QDs) grown on Ge (001) substrates by molecular beam epitaxy. Anti-phase domains (APDs) of GaAs are distributed on Ge substrate after the growth of GaAs due to the growth nature of III–V compound on group IV semiconductors having polar and non-polar behaviors. The APDs affect the QD growth as demonstrated by the growth of conventional InAs QDs on this surface. For GaSb QDs, the GaSb layer is grown on GaAs APD surface and compared with the GaSb layer on conventional (001) GaAs surface. Self-assembled QDs are formed on both surfaces but structural analysis reveals evidence of shape and size differences, which is attributed to the influence of the initial surface. Photoluminescence of GaSb/GaAs QDs grown on both Ge and GaAs substrates is studied. Emission from GaSb/GaAs QDs on Ge substrate can be detected till near room temperature (270 K).

Journal of Crystal Growth, 1997

Lines of local epitaxy of GaAsGaAlAs multiple quantum wells with linewidth of 7 and 5 μm having l... more Lines of local epitaxy of GaAsGaAlAs multiple quantum wells with linewidth of 7 and 5 μm having line separation of 250 μm were fabricated by molecular beam epitaxy (MBE) using shadow masking technique. Photoluminescence (PL) measurements at 10 K were performed by using an argon laser with cylindrical lens producing line focus and with circular lens producing point focus for the excitation. The focussed line and focussed point of laser beam were ∼ 100 μm and could be aligned to the stripes of MQW. The PL spectrum characteristics reflect the quantum well structure as well as the crystal quality of shadow masked epitaxy layers. The PL spectrum shows double PL peaks at 758 and 774 nm with nearly equal intensity when the exciting beam lined parallel to the stripes of MQW have a 7 μm window and quantum well width of 30 monolayers. Overlapping PL peaks at 810 and 818 nm were observed from MQW having 5 μm window and quantum well width of 60 monolayers. Similar results were obtained by point focussed laser beam and by line focussed laser beam at perpendicular configuration. A stronger PL peak at 818 nm was clearly emphasized by strip-off MQW samples having 5 μm stripes. The PL peak from a shadow masked MQW sample was sharp having spectral FWHM of 14 nm and was relatively stronger than that obtained from conventional MQW samples. These experimental data indicated that MBE grown MQW mesa using shadow masking technique is suitable for quantum device fabrication.

Journal of Crystal Growth, 2001

Self-organized InAs QDs formation on (4 1 1)A GaAs and on controlled (1 0 0) GaAs substrates were... more Self-organized InAs QDs formation on (4 1 1)A GaAs and on controlled (1 0 0) GaAs substrates were studied by insitu RHEED observation, AFM measurement and PL spectroscopy. The transition from two-dimensional to threedimensional 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 3stacked 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 (411)A. #