The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
D. Garbuzov - One of the best experts on this subject based on the ideXlab platform.
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Photoluminescence study of Excess Carrier spillover in 1.3 μm wavelength strained multi‐quantum‐well InGaAsP/InP laser structures
Applied Physics Letters, 1995Co-Authors: D. Garbuzov, G.-j. Shiau, Vladimir Bulovic, M. Boroditsky, C.-p. Chao, S. R. ForrestAbstract:Photoluminescence of 1.3 μm wavelength strained multiple quantum well InGaAsP/InP laser structures has been used to understand the Excess Carrier redistribution between the quantum well and waveguide regions at a high level of excitation. A model is developed to describe the experimental results. The model suggests that space charge barriers play a significant role in the electron confinement in quantum wells at the high excitation range typical of laser diode operation.
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photoluminescence study of Excess Carrier spillover in 1 3 μm wavelength strained multi quantum well ingaasp inp laser structures
Applied Physics Letters, 1995Co-Authors: D. Garbuzov, G.-j. Shiau, Vladimir Bulovic, M. Boroditsky, C.-p. Chao, S. R. ForrestAbstract:Photoluminescence of 1.3 μm wavelength strained multiple quantum well InGaAsP/InP laser structures has been used to understand the Excess Carrier redistribution between the quantum well and waveguide regions at a high level of excitation. A model is developed to describe the experimental results. The model suggests that space charge barriers play a significant role in the electron confinement in quantum wells at the high excitation range typical of laser diode operation.
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Efficiency of photoluminescence and Excess Carrier confinement in InGaAsP/GaAs structures prepared by metal‐organic chemical‐vapor deposition
Journal of Applied Physics, 1994Co-Authors: Jacqueline E. Diaz, M. Erdtmann, E. Kolev, D. Garbuzov, E. Bigan, Manijeh RazeghiAbstract:Special double‐ and separate‐confinement InGaAsP/GaAs heterostructures intended for photoluminescence measurements have been grown by low‐pressure metal‐organic chemical‐vapor deposition. The band gap of the active region quaternary material was close to 1.5 eV, and the waveguide of the separate‐confinement structures was near 1.8 eV. Measurement of the integrated luminescence efficiency at 300 K has shown that over a wide range of excitation level (10–103 W/cm2) radiative transitions are the dominant mechanism for Excess Carrier recombination in the active region of the structures studied. As determined by spectral measurements, the Excess Carrier concentration in the waveguide of the separate‐confinement heterostructures and the intensity of the waveguide emission band correspond to a condition of thermal equilibrium of the Excess Carrier populations in the active region and the waveguide. The ratio of the intensity of the waveguide emission to the active region emission fits a model which assumes that the barrier height for minority Carriers (holes) is equal to the difference in band gaps between the active region and the waveguide region.
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efficiency of photoluminescence and Excess Carrier confinement in ingaasp gaas structures prepared by metal organic chemical vapor deposition
Journal of Applied Physics, 1994Co-Authors: J Diaz, M. Erdtmann, E. Kolev, D. Garbuzov, E. Bigan, Manijeh RazeghiAbstract:Special double‐ and separate‐confinement InGaAsP/GaAs heterostructures intended for photoluminescence measurements have been grown by low‐pressure metal‐organic chemical‐vapor deposition. The band gap of the active region quaternary material was close to 1.5 eV, and the waveguide of the separate‐confinement structures was near 1.8 eV. Measurement of the integrated luminescence efficiency at 300 K has shown that over a wide range of excitation level (10–103 W/cm2) radiative transitions are the dominant mechanism for Excess Carrier recombination in the active region of the structures studied. As determined by spectral measurements, the Excess Carrier concentration in the waveguide of the separate‐confinement heterostructures and the intensity of the waveguide emission band correspond to a condition of thermal equilibrium of the Excess Carrier populations in the active region and the waveguide. The ratio of the intensity of the waveguide emission to the active region emission fits a model which assumes that the barrier height for minority Carriers (holes) is equal to the difference in band gaps between the active region and the waveguide region.
S. R. Forrest - One of the best experts on this subject based on the ideXlab platform.
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Photoluminescence study of Excess Carrier spillover in 1.3 μm wavelength strained multi‐quantum‐well InGaAsP/InP laser structures
Applied Physics Letters, 1995Co-Authors: D. Garbuzov, G.-j. Shiau, Vladimir Bulovic, M. Boroditsky, C.-p. Chao, S. R. ForrestAbstract:Photoluminescence of 1.3 μm wavelength strained multiple quantum well InGaAsP/InP laser structures has been used to understand the Excess Carrier redistribution between the quantum well and waveguide regions at a high level of excitation. A model is developed to describe the experimental results. The model suggests that space charge barriers play a significant role in the electron confinement in quantum wells at the high excitation range typical of laser diode operation.
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photoluminescence study of Excess Carrier spillover in 1 3 μm wavelength strained multi quantum well ingaasp inp laser structures
Applied Physics Letters, 1995Co-Authors: D. Garbuzov, G.-j. Shiau, Vladimir Bulovic, M. Boroditsky, C.-p. Chao, S. R. ForrestAbstract:Photoluminescence of 1.3 μm wavelength strained multiple quantum well InGaAsP/InP laser structures has been used to understand the Excess Carrier redistribution between the quantum well and waveguide regions at a high level of excitation. A model is developed to describe the experimental results. The model suggests that space charge barriers play a significant role in the electron confinement in quantum wells at the high excitation range typical of laser diode operation.
Masaya Ichimura - One of the best experts on this subject based on the ideXlab platform.
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Correlation between Microwave Reflectivity and Excess Carrier Concentrations in 4H-SiC
Materials Science Forum, 2014Co-Authors: Masashi Kato, Yuto Mori, Masaya IchimuraAbstract:Carrier lifetime in a high injection condition is a key parameter for design of bipolar devices. Microwave photoconductivity decay (μ-PCD) is a popular method to evaluate the Carrier lifetime in silicon carbide (SiC). For accurate evaluation of the Carrier lifetime by μ-PCD measurements, the microwave reflectivity needs to be proportional to the Excess Carrier concentration. In this study, we observed microwave reflectivity from 4H-SiC as a function of injected photon density and suggested a method to keep proportionality of the reflectivity to the Excess Carrier concentration.
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Excess Carrier lifetime and strain distributions in a 3C‐SiC wafer grown on an undulant Si substrate
physica status solidi (a), 2013Co-Authors: Masashi Kato, Masaya Ichimura, Atsushi Yoshida, Hiroyuki NagasawaAbstract:In this study, we have used the microwave photoconductivity decay method to map Excess Carrier lifetimes in a n-type 3C-SiC wafer grown on an undulant Si substrate. We compared these lifetime maps with the distributions of strains and defects, which were observed using optical microscopy, Raman spectroscopy and pit distributions after molten NaOH etching. We found that Excess Carrier lifetimes in strained regions, which exhibit high densities of defects, are short. We also found that Carrier lifetimes in strained regions at the cross sections of the 3C-SiC wafer are short. These results suggest that defects and strains in the wafer exhibit distributions similar to those of shortened Carrier lifetimes. Excess Carrier lifetime map for a 3C-SiC wafer.
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Excess Carrier Lifetime in p-Type 4H-SiC Epilayers with and without Low-Energy Electron Irradiation
Japanese Journal of Applied Physics, 2012Co-Authors: Masashi Kato, Masaya Ichimura, Yoshinori Matsushita, Tomoaki Hatayama, Takeshi OhshimaAbstract:We measured Excess Carrier lifetimes in as-grown and low-energy electron-irradiated p-type 4H-SiC epitaxial layers by the microwave photoconductivity decay method. The Carrier lifetime increases with the excitation density in the epilayers. This dependence suggests that the dominant recombination center in the epilayers has a larger capture cross section for electrons than for holes. The low-energy electron irradiation reduces the Carrier lifetime in the epilayers, and 1000 °C annealing increases the Carrier lifetime in the electron-irradiated samples.
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Correlation between Strain and Excess Carrier Lifetime in a 3C-SiC Wafer
Materials Science Forum, 2012Co-Authors: Atsushi Yoshida, Masashi Kato, Masaya IchimuraAbstract:We obtained Excess Carrier lifetime maps by the microwave photoconductivity decay (µ-PCD) method in a free-standing n-type 3C-SiC wafer, and then we compared the lifetime maps with distributions of strains and defects observed by the optical microscopy and the Raman spectroscopy. We found that the Excess Carrier lifetimes are short in a strained region in 3C-SiC, which indicates that structural defects exist around a strained region.
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characterization of the Excess Carrier lifetime of as grown and electron irradiated epitaxial p type 4h sic layers by the microwave photoconductivity decay method
Materials Science Forum, 2010Co-Authors: Yoshinori Matsushita, Masaya Ichimura, Masashi Kato, Tomoaki Hatayama, Takeshi OhshimaAbstract:We measured the Excess Carrier lifetimes in as-grown and electron irradiated p-type 4H-SiC epitaxial layers with the microwave photoconductivity decay (-PCD) method. The Carrier lifetime becomes longer with excitation density for the as-grown epilayer. This dependence suggests that e ≥h for the dominant recombination center, where e andh are capture cross sections for electrons and holes, respectively. In contrast, the Carrier lifetime does not depend on the excitation density for the sample irradiated with electrons at an energy of 160 keV and a dose of 1×1017 cm-2. This may be due to the fact that recombination centers with e
Stefan Dalakov - One of the best experts on this subject based on the ideXlab platform.
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New experimental approach to the Excess Carrier transfer in semi‐insulating GaAs based on time‐resolved photovoltage
Applied Physics Letters, 1995Co-Authors: Chavdar Hardalov, Dobri Atanassov Batovski, Stefan DalakovAbstract:The photovoltage shows a very complicated behavior and could be considered as a new approach to the investigation of the Excess Carrier transfer in semi‐insulating (SI) semiconductors. Both time‐resolved short‐circuit (SC) photovoltage and photocurrent at the same energies in the range 1.13–1.49 eV for SI GaAs were measured. The peculiarities of the photovoltage were explained in terms of hole transfer between EL2 deep center and a series of acceptor levels. The influence of the electrons and holes was distinguished, which is known to be impossible via conventional photocurrent measurements.
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new experimental approach to the Excess Carrier transfer in semi insulating gaas based on time resolved photovoltage
Applied Physics Letters, 1995Co-Authors: Chavdar Hardalov, Dobri Atanassov Batovski, Stefan DalakovAbstract:The photovoltage shows a very complicated behavior and could be considered as a new approach to the investigation of the Excess Carrier transfer in semi‐insulating (SI) semiconductors. Both time‐resolved short‐circuit (SC) photovoltage and photocurrent at the same energies in the range 1.13–1.49 eV for SI GaAs were measured. The peculiarities of the photovoltage were explained in terms of hole transfer between EL2 deep center and a series of acceptor levels. The influence of the electrons and holes was distinguished, which is known to be impossible via conventional photocurrent measurements.
Masashi Kato - One of the best experts on this subject based on the ideXlab platform.
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Correlation between Microwave Reflectivity and Excess Carrier Concentrations in 4H-SiC
Materials Science Forum, 2014Co-Authors: Masashi Kato, Yuto Mori, Masaya IchimuraAbstract:Carrier lifetime in a high injection condition is a key parameter for design of bipolar devices. Microwave photoconductivity decay (μ-PCD) is a popular method to evaluate the Carrier lifetime in silicon carbide (SiC). For accurate evaluation of the Carrier lifetime by μ-PCD measurements, the microwave reflectivity needs to be proportional to the Excess Carrier concentration. In this study, we observed microwave reflectivity from 4H-SiC as a function of injected photon density and suggested a method to keep proportionality of the reflectivity to the Excess Carrier concentration.
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Excess Carrier lifetime and strain distributions in a 3C‐SiC wafer grown on an undulant Si substrate
physica status solidi (a), 2013Co-Authors: Masashi Kato, Masaya Ichimura, Atsushi Yoshida, Hiroyuki NagasawaAbstract:In this study, we have used the microwave photoconductivity decay method to map Excess Carrier lifetimes in a n-type 3C-SiC wafer grown on an undulant Si substrate. We compared these lifetime maps with the distributions of strains and defects, which were observed using optical microscopy, Raman spectroscopy and pit distributions after molten NaOH etching. We found that Excess Carrier lifetimes in strained regions, which exhibit high densities of defects, are short. We also found that Carrier lifetimes in strained regions at the cross sections of the 3C-SiC wafer are short. These results suggest that defects and strains in the wafer exhibit distributions similar to those of shortened Carrier lifetimes. Excess Carrier lifetime map for a 3C-SiC wafer.
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Excess Carrier Lifetime in p-Type 4H-SiC Epilayers with and without Low-Energy Electron Irradiation
Japanese Journal of Applied Physics, 2012Co-Authors: Masashi Kato, Masaya Ichimura, Yoshinori Matsushita, Tomoaki Hatayama, Takeshi OhshimaAbstract:We measured Excess Carrier lifetimes in as-grown and low-energy electron-irradiated p-type 4H-SiC epitaxial layers by the microwave photoconductivity decay method. The Carrier lifetime increases with the excitation density in the epilayers. This dependence suggests that the dominant recombination center in the epilayers has a larger capture cross section for electrons than for holes. The low-energy electron irradiation reduces the Carrier lifetime in the epilayers, and 1000 °C annealing increases the Carrier lifetime in the electron-irradiated samples.
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Correlation between Strain and Excess Carrier Lifetime in a 3C-SiC Wafer
Materials Science Forum, 2012Co-Authors: Atsushi Yoshida, Masashi Kato, Masaya IchimuraAbstract:We obtained Excess Carrier lifetime maps by the microwave photoconductivity decay (µ-PCD) method in a free-standing n-type 3C-SiC wafer, and then we compared the lifetime maps with distributions of strains and defects observed by the optical microscopy and the Raman spectroscopy. We found that the Excess Carrier lifetimes are short in a strained region in 3C-SiC, which indicates that structural defects exist around a strained region.
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characterization of the Excess Carrier lifetime of as grown and electron irradiated epitaxial p type 4h sic layers by the microwave photoconductivity decay method
Materials Science Forum, 2010Co-Authors: Yoshinori Matsushita, Masaya Ichimura, Masashi Kato, Tomoaki Hatayama, Takeshi OhshimaAbstract:We measured the Excess Carrier lifetimes in as-grown and electron irradiated p-type 4H-SiC epitaxial layers with the microwave photoconductivity decay (-PCD) method. The Carrier lifetime becomes longer with excitation density for the as-grown epilayer. This dependence suggests that e ≥h for the dominant recombination center, where e andh are capture cross sections for electrons and holes, respectively. In contrast, the Carrier lifetime does not depend on the excitation density for the sample irradiated with electrons at an energy of 160 keV and a dose of 1×1017 cm-2. This may be due to the fact that recombination centers with e
