The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Hyuckin Kwon - One of the best experts on this subject based on the ideXlab platform.
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charge trapping and detrapping characteristics in amorphous ingazno tfts under static and dynamic stresses
Semiconductor Science and Technology, 2009Co-Authors: Intak Cho, Jeongmin Lee, Jongho Lee, Hyuckin KwonAbstract:We have investigated the static and dynamic bias stress-induced charge trapping and detrapping phenomenon in amorphous indium–gallium–zinc oxide thin film transistors. It is observed that the charges trapped after electron injection in the interface and bulk traps are unstable and slowly decay over time. The stretched-Exponential Equation, which can be derived based on the trapping/detrapping of charges to/from existing traps and continuous redistribution of charges in bulk dielectrics, is successfully applied in fitting the time dependence of the threshold voltage shift during the stress and recovery phases under dynamic stresses. The characteristic time constants decrease with increasing temperature and drain bias during the recovery phase. Under dynamic stresses with various frequencies, the threshold voltage shift strongly depends on the frequency of dynamic stresses, i.e., a high frequency stress results in a small threshold voltage shift and a long lifetime. The stress-induced threshold shift phenomenon is observed to be relieved after a long-time low temperature post thermal annealing process and device passivation with an aluminum oxide layer.
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bias stress induced stretched Exponential time dependence of threshold voltage shift in ingazno thin film transistors
Applied Physics Letters, 2008Co-Authors: Jeongmin Lee, Intak Cho, Jongho Lee, Hyuckin KwonAbstract:The experimental and modeling study of bias-stress-induced threshold voltage instabilities in amorphous indium-gallium-zinc oxide thin film transistors is reported. Positive stress results in a positive shift in the threshold voltage, while the transfer curve hardly moves when negative stress is induced. The time evolution of threshold voltage is described by the stretched-Exponential Equation, and the shift is attributed to the electron injection from the channel into interface/dielectric traps. The stress amplitudes and stress temperatures are considered as important factors in threshold voltage instabilities, and the stretched-Exponential Equation is well fitted in various bias temperature stress conditions.
Yuichi Onda - One of the best experts on this subject based on the ideXlab platform.
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vertical distribution and temporal changes of 137cs in soil profiles under various land uses after the fukushima dai ichi nuclear power plant accident
Journal of Environmental Radioactivity, 2015Co-Authors: Junko Takahashi, Kenji Tamura, Tomoya Suda, Ryo Matsumura, Yuichi OndaAbstract:Abstract We monitored the vertical distribution of 137Cs in soil profiles under eight different land uses for the 2 y after the Fukushima Dai-ichi Nuclear Power Plant accident, and discussed the temporal changes in the early-stage of the migration and the determinants of the initial distribution. The soil samples were collected for four surveys using a scraper plate at each study site, which consisted of three forests (mixed forest, mature cedar, and young cedar), two grasslands (pasture and meadow) and three abandoned agricultural fields (farm land, tobacco field, and paddy field). The land use patterns have a large influence on some soil properties and the migration processes of 137Cs above ground, resulting in different distribution of 137Cs in those soil profiles. Specifically, the secondary deposition of 137Cs from the coniferous canopy, retention of 137Cs by litter layer, and the homogenization of 137Cs concentrations in surface soil by natural soil mixing such as the disturbance by cattle grazing, roots growing and the formation of needle ice were important to cause redistribution of the deposited 137Cs. Only in the paddy field, the 137Cs inventory in subsurface soils (5–10 cm) gradually increased and comprised 26% of the total 137Cs in 2 y, showing the downward migration of 137Cs to subsurface soil. In the other sites, it was considered that 137Cs were strongly adsorbed by soil particles and rarely migrated downward as soluble form. Vertical distributions during the first survey were able to be used as the initial distributions and were well fitted to the Exponential Equation. The distribution parameters α (relaxation depth) and β (relaxation mass depth), calculated by the Exponential Equation were correlated with RIP (r = −0.806, p
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vertical distribution and temporal changes of 137cs in soil profiles under various land uses after the fukushima dai ichi nuclear power plant accident
Journal of Environmental Radioactivity, 2015Co-Authors: Junko Takahashi, Kenji Tamura, Tomoya Suda, Ryo Matsumura, Yuichi OndaAbstract:We monitored the vertical distribution of 137Cs in soil profiles under eight different land uses for the 2 y after the Fukushima Dai-ichi Nuclear Power Plant accident, and discussed the temporal changes in the early-stage of the migration and the determinants of the initial distribution. The soil samples were collected for four surveys using a scraper plate at each study site, which consisted of three forests (mixed forest, mature cedar, and young cedar), two grasslands (pasture and meadow) and three abandoned agricultural fields (farm land, tobacco field, and paddy field). The land use patterns have a large influence on some soil properties and the migration processes of 137Cs above ground, resulting in different distribution of 137Cs in those soil profiles. Specifically, the secondary deposition of 137Cs from the coniferous canopy, retention of 137Cs by litter layer, and the homogenization of 137Cs concentrations in surface soil by natural soil mixing such as the disturbance by cattle grazing, roots growing and the formation of needle ice were important to cause redistribution of the deposited 137Cs. Only in the paddy field, the 137Cs inventory in subsurface soils (5–10 cm) gradually increased and comprised 26% of the total 137Cs in 2 y, showing the downward migration of 137Cs to subsurface soil. In the other sites, it was considered that 137Cs were strongly adsorbed by soil particles and rarely migrated downward as soluble form. Vertical distributions during the first survey were able to be used as the initial distributions and were well fitted to the Exponential Equation. The distribution parameters α (relaxation depth) and β (relaxation mass depth), calculated by the Exponential Equation were correlated with RIP (r = −0.806, p < 0.05), macro pore (r = 0.651, p = 0.11), and dispersible fine particle content (r = 0.856, p < 0.05). It indicated that the initial distribution would be influenced by the Cs fixation ability of soil, and the penetration process of water and particles in soils.
Jeongmin Lee - One of the best experts on this subject based on the ideXlab platform.
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charge trapping and detrapping characteristics in amorphous ingazno tfts under static and dynamic stresses
Semiconductor Science and Technology, 2009Co-Authors: Intak Cho, Jeongmin Lee, Jongho Lee, Hyuckin KwonAbstract:We have investigated the static and dynamic bias stress-induced charge trapping and detrapping phenomenon in amorphous indium–gallium–zinc oxide thin film transistors. It is observed that the charges trapped after electron injection in the interface and bulk traps are unstable and slowly decay over time. The stretched-Exponential Equation, which can be derived based on the trapping/detrapping of charges to/from existing traps and continuous redistribution of charges in bulk dielectrics, is successfully applied in fitting the time dependence of the threshold voltage shift during the stress and recovery phases under dynamic stresses. The characteristic time constants decrease with increasing temperature and drain bias during the recovery phase. Under dynamic stresses with various frequencies, the threshold voltage shift strongly depends on the frequency of dynamic stresses, i.e., a high frequency stress results in a small threshold voltage shift and a long lifetime. The stress-induced threshold shift phenomenon is observed to be relieved after a long-time low temperature post thermal annealing process and device passivation with an aluminum oxide layer.
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bias stress induced stretched Exponential time dependence of threshold voltage shift in ingazno thin film transistors
Applied Physics Letters, 2008Co-Authors: Jeongmin Lee, Intak Cho, Jongho Lee, Hyuckin KwonAbstract:The experimental and modeling study of bias-stress-induced threshold voltage instabilities in amorphous indium-gallium-zinc oxide thin film transistors is reported. Positive stress results in a positive shift in the threshold voltage, while the transfer curve hardly moves when negative stress is induced. The time evolution of threshold voltage is described by the stretched-Exponential Equation, and the shift is attributed to the electron injection from the channel into interface/dielectric traps. The stress amplitudes and stress temperatures are considered as important factors in threshold voltage instabilities, and the stretched-Exponential Equation is well fitted in various bias temperature stress conditions.
Intak Cho - One of the best experts on this subject based on the ideXlab platform.
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charge trapping and detrapping characteristics in amorphous ingazno tfts under static and dynamic stresses
Semiconductor Science and Technology, 2009Co-Authors: Intak Cho, Jeongmin Lee, Jongho Lee, Hyuckin KwonAbstract:We have investigated the static and dynamic bias stress-induced charge trapping and detrapping phenomenon in amorphous indium–gallium–zinc oxide thin film transistors. It is observed that the charges trapped after electron injection in the interface and bulk traps are unstable and slowly decay over time. The stretched-Exponential Equation, which can be derived based on the trapping/detrapping of charges to/from existing traps and continuous redistribution of charges in bulk dielectrics, is successfully applied in fitting the time dependence of the threshold voltage shift during the stress and recovery phases under dynamic stresses. The characteristic time constants decrease with increasing temperature and drain bias during the recovery phase. Under dynamic stresses with various frequencies, the threshold voltage shift strongly depends on the frequency of dynamic stresses, i.e., a high frequency stress results in a small threshold voltage shift and a long lifetime. The stress-induced threshold shift phenomenon is observed to be relieved after a long-time low temperature post thermal annealing process and device passivation with an aluminum oxide layer.
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bias stress induced stretched Exponential time dependence of threshold voltage shift in ingazno thin film transistors
Applied Physics Letters, 2008Co-Authors: Jeongmin Lee, Intak Cho, Jongho Lee, Hyuckin KwonAbstract:The experimental and modeling study of bias-stress-induced threshold voltage instabilities in amorphous indium-gallium-zinc oxide thin film transistors is reported. Positive stress results in a positive shift in the threshold voltage, while the transfer curve hardly moves when negative stress is induced. The time evolution of threshold voltage is described by the stretched-Exponential Equation, and the shift is attributed to the electron injection from the channel into interface/dielectric traps. The stress amplitudes and stress temperatures are considered as important factors in threshold voltage instabilities, and the stretched-Exponential Equation is well fitted in various bias temperature stress conditions.
Junko Takahashi - One of the best experts on this subject based on the ideXlab platform.
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vertical distribution and temporal changes of 137cs in soil profiles under various land uses after the fukushima dai ichi nuclear power plant accident
Journal of Environmental Radioactivity, 2015Co-Authors: Junko Takahashi, Kenji Tamura, Tomoya Suda, Ryo Matsumura, Yuichi OndaAbstract:Abstract We monitored the vertical distribution of 137Cs in soil profiles under eight different land uses for the 2 y after the Fukushima Dai-ichi Nuclear Power Plant accident, and discussed the temporal changes in the early-stage of the migration and the determinants of the initial distribution. The soil samples were collected for four surveys using a scraper plate at each study site, which consisted of three forests (mixed forest, mature cedar, and young cedar), two grasslands (pasture and meadow) and three abandoned agricultural fields (farm land, tobacco field, and paddy field). The land use patterns have a large influence on some soil properties and the migration processes of 137Cs above ground, resulting in different distribution of 137Cs in those soil profiles. Specifically, the secondary deposition of 137Cs from the coniferous canopy, retention of 137Cs by litter layer, and the homogenization of 137Cs concentrations in surface soil by natural soil mixing such as the disturbance by cattle grazing, roots growing and the formation of needle ice were important to cause redistribution of the deposited 137Cs. Only in the paddy field, the 137Cs inventory in subsurface soils (5–10 cm) gradually increased and comprised 26% of the total 137Cs in 2 y, showing the downward migration of 137Cs to subsurface soil. In the other sites, it was considered that 137Cs were strongly adsorbed by soil particles and rarely migrated downward as soluble form. Vertical distributions during the first survey were able to be used as the initial distributions and were well fitted to the Exponential Equation. The distribution parameters α (relaxation depth) and β (relaxation mass depth), calculated by the Exponential Equation were correlated with RIP (r = −0.806, p
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vertical distribution and temporal changes of 137cs in soil profiles under various land uses after the fukushima dai ichi nuclear power plant accident
Journal of Environmental Radioactivity, 2015Co-Authors: Junko Takahashi, Kenji Tamura, Tomoya Suda, Ryo Matsumura, Yuichi OndaAbstract:We monitored the vertical distribution of 137Cs in soil profiles under eight different land uses for the 2 y after the Fukushima Dai-ichi Nuclear Power Plant accident, and discussed the temporal changes in the early-stage of the migration and the determinants of the initial distribution. The soil samples were collected for four surveys using a scraper plate at each study site, which consisted of three forests (mixed forest, mature cedar, and young cedar), two grasslands (pasture and meadow) and three abandoned agricultural fields (farm land, tobacco field, and paddy field). The land use patterns have a large influence on some soil properties and the migration processes of 137Cs above ground, resulting in different distribution of 137Cs in those soil profiles. Specifically, the secondary deposition of 137Cs from the coniferous canopy, retention of 137Cs by litter layer, and the homogenization of 137Cs concentrations in surface soil by natural soil mixing such as the disturbance by cattle grazing, roots growing and the formation of needle ice were important to cause redistribution of the deposited 137Cs. Only in the paddy field, the 137Cs inventory in subsurface soils (5–10 cm) gradually increased and comprised 26% of the total 137Cs in 2 y, showing the downward migration of 137Cs to subsurface soil. In the other sites, it was considered that 137Cs were strongly adsorbed by soil particles and rarely migrated downward as soluble form. Vertical distributions during the first survey were able to be used as the initial distributions and were well fitted to the Exponential Equation. The distribution parameters α (relaxation depth) and β (relaxation mass depth), calculated by the Exponential Equation were correlated with RIP (r = −0.806, p < 0.05), macro pore (r = 0.651, p = 0.11), and dispersible fine particle content (r = 0.856, p < 0.05). It indicated that the initial distribution would be influenced by the Cs fixation ability of soil, and the penetration process of water and particles in soils.
