The Experts below are selected from a list of 150597 Experts worldwide ranked by ideXlab platform
Paul R Berger - One of the best experts on this subject based on the ideXlab platform.
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930 ka cm 2 peak tunneling current density in gan aln resonant tunneling diodes grown on mocvd gan on sapphire template
Applied Physics Letters, 2019Co-Authors: Tyler A Growden, E R Brown, D F Storm, David J Meyer, Weidong Zhang, Evan M Cornuelle, Logan M Whitaker, Jeffrey W Daulton, R J Molnar, Paul R BergerAbstract:We report on the design and fabrication of ultrahigh current density GaN/AlN double barrier resonant tunneling diodes grown via rf-plasma assisted molecular-beam epitaxy. The device structure was grown on a metal-organic chemical vapor deposition GaN-on-sapphire template. The devices displayed repeatable room temperature negative differential resistance with peak tunneling current densities (Jp) between 637 and 930 kA/cm2. Analysis of temperature dependent measurements revealed the presence of severe self-heating effects, which allow strong phonon scattering that deteriorates the electron quantum transport. Finally, a Qualitative Comparison to the same structure grown on a low dislocation density freestanding GaN substrate has shown that sapphire-based templates are a feasible alternative.We report on the design and fabrication of ultrahigh current density GaN/AlN double barrier resonant tunneling diodes grown via rf-plasma assisted molecular-beam epitaxy. The device structure was grown on a metal-organic chemical vapor deposition GaN-on-sapphire template. The devices displayed repeatable room temperature negative differential resistance with peak tunneling current densities (Jp) between 637 and 930 kA/cm2. Analysis of temperature dependent measurements revealed the presence of severe self-heating effects, which allow strong phonon scattering that deteriorates the electron quantum transport. Finally, a Qualitative Comparison to the same structure grown on a low dislocation density freestanding GaN substrate has shown that sapphire-based templates are a feasible alternative.
K V Suneeth - One of the best experts on this subject based on the ideXlab platform.
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assessment of vertical air motion among reanalyses and Qualitative Comparison with very high frequency radar measurements over two tropical stations
Atmospheric Chemistry and Physics, 2021Co-Authors: K N Uma, Siddarth Shankar Das, Madineni Venkat Ratnam, K V SuneethAbstract:Abstract. Vertical wind ( w ) is one of the most important meteorological parameters for understanding a range of different atmospheric phenomena. Very few direct measurements of w are available so that most of the time one must depend on reanalysis products. In the present study, assessment of w among selected reanalyses (ERA-Interim, ERAi; ERA fifth generation, ERA5; Modern-Era Retrospective analysis for Research and Applications, version 2, MERRA-2; National Center for Atmospheric Research and Depart- ment of Energy reanalysis, NCEP–DOE (R-2); and Japanese 55-year reanalysis, JRA-55) and Qualitative Comparison of those datasets with VHF radar measurements over the convectively active regions Gadanki, India (13.5 ∘ N, 79.2 ∘ E), and Kototabang, Indonesia (0 ∘ S, 100.2 ∘ E), are presented for the first time in the troposphere and lower stratosphere. The magnitude of w derived from reanalyses is 10 %–50 % less than that from the radar observations. Radar measurements of w show downdrafts below 8 and 10 km and updrafts above 8–10 km over both locations. InterComparison between the ensemble of reanalyses with respect to individual reanalysis shows that ERAi, MERRA-2 and JRA-55 compare well with the ensemble compared to ERA5 and NCEP–DOE (R-2). There is no significant improvement in w due to the effect of different spatial sampling for reanalysis data around the Gadanki station. Directional tendency shows that the percentage of updrafts captured is reasonably good, but downdrafts are not well captured by all reanalyses. Thus, caution is advised when using w from reanalyses.
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assessment of vertical air motion among reanalyses and Qualitative Comparison with direct vhf radar measurements over the two tropical stations
Atmospheric Chemistry and Physics, 2020Co-Authors: K N Uma, Siddarth Shankar Das, Madineni Venkat Ratnam, K V SuneethAbstract:Abstract. Vertical wind (w) is one of the most important meteorological parameters for understanding different atmospheric phenomena. Only very few direct measurements of w are available and most of the time one must depend on reanalysis products. In the present study, assessment of w among selected reanalyses, (ERA-Interim, ERA-5, MERRA-2, NCEP-2 and JRA-55) and Qualitative Comparison of those datasets with direct VHF radar measurements over the convectively active regions Gadanki (13.5° N and 79.2° E) and Kototabang (0° S and 100.2° E) are presented for the first time. The magnitude of w derived from reanalyses is 10–50 % less than that from the direct radar observations. Radar measurements of w show downdrafts below 8 to 10 km and updrafts above 8–10 km over both locations. Inter-Comparison between the reanalyses shows that ERAi is overestimating NCEP-2 and underestimating all the reanalyses. Directional tendency shows that the percentage of updrafts captured is reasonably good, but downdrafts are not well captured by all reanalyses. Thus, caution is advised when using vertical velocities from reanalyses.
Tyler A Growden - One of the best experts on this subject based on the ideXlab platform.
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930 ka cm 2 peak tunneling current density in gan aln resonant tunneling diodes grown on mocvd gan on sapphire template
Applied Physics Letters, 2019Co-Authors: Tyler A Growden, E R Brown, D F Storm, David J Meyer, Weidong Zhang, Evan M Cornuelle, Logan M Whitaker, Jeffrey W Daulton, R J Molnar, Paul R BergerAbstract:We report on the design and fabrication of ultrahigh current density GaN/AlN double barrier resonant tunneling diodes grown via rf-plasma assisted molecular-beam epitaxy. The device structure was grown on a metal-organic chemical vapor deposition GaN-on-sapphire template. The devices displayed repeatable room temperature negative differential resistance with peak tunneling current densities (Jp) between 637 and 930 kA/cm2. Analysis of temperature dependent measurements revealed the presence of severe self-heating effects, which allow strong phonon scattering that deteriorates the electron quantum transport. Finally, a Qualitative Comparison to the same structure grown on a low dislocation density freestanding GaN substrate has shown that sapphire-based templates are a feasible alternative.We report on the design and fabrication of ultrahigh current density GaN/AlN double barrier resonant tunneling diodes grown via rf-plasma assisted molecular-beam epitaxy. The device structure was grown on a metal-organic chemical vapor deposition GaN-on-sapphire template. The devices displayed repeatable room temperature negative differential resistance with peak tunneling current densities (Jp) between 637 and 930 kA/cm2. Analysis of temperature dependent measurements revealed the presence of severe self-heating effects, which allow strong phonon scattering that deteriorates the electron quantum transport. Finally, a Qualitative Comparison to the same structure grown on a low dislocation density freestanding GaN substrate has shown that sapphire-based templates are a feasible alternative.
David J Meyer - One of the best experts on this subject based on the ideXlab platform.
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930 ka cm 2 peak tunneling current density in gan aln resonant tunneling diodes grown on mocvd gan on sapphire template
Applied Physics Letters, 2019Co-Authors: Tyler A Growden, E R Brown, D F Storm, David J Meyer, Weidong Zhang, Evan M Cornuelle, Logan M Whitaker, Jeffrey W Daulton, R J Molnar, Paul R BergerAbstract:We report on the design and fabrication of ultrahigh current density GaN/AlN double barrier resonant tunneling diodes grown via rf-plasma assisted molecular-beam epitaxy. The device structure was grown on a metal-organic chemical vapor deposition GaN-on-sapphire template. The devices displayed repeatable room temperature negative differential resistance with peak tunneling current densities (Jp) between 637 and 930 kA/cm2. Analysis of temperature dependent measurements revealed the presence of severe self-heating effects, which allow strong phonon scattering that deteriorates the electron quantum transport. Finally, a Qualitative Comparison to the same structure grown on a low dislocation density freestanding GaN substrate has shown that sapphire-based templates are a feasible alternative.We report on the design and fabrication of ultrahigh current density GaN/AlN double barrier resonant tunneling diodes grown via rf-plasma assisted molecular-beam epitaxy. The device structure was grown on a metal-organic chemical vapor deposition GaN-on-sapphire template. The devices displayed repeatable room temperature negative differential resistance with peak tunneling current densities (Jp) between 637 and 930 kA/cm2. Analysis of temperature dependent measurements revealed the presence of severe self-heating effects, which allow strong phonon scattering that deteriorates the electron quantum transport. Finally, a Qualitative Comparison to the same structure grown on a low dislocation density freestanding GaN substrate has shown that sapphire-based templates are a feasible alternative.
Weidong Zhang - One of the best experts on this subject based on the ideXlab platform.
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930 ka cm 2 peak tunneling current density in gan aln resonant tunneling diodes grown on mocvd gan on sapphire template
Applied Physics Letters, 2019Co-Authors: Tyler A Growden, E R Brown, D F Storm, David J Meyer, Weidong Zhang, Evan M Cornuelle, Logan M Whitaker, Jeffrey W Daulton, R J Molnar, Paul R BergerAbstract:We report on the design and fabrication of ultrahigh current density GaN/AlN double barrier resonant tunneling diodes grown via rf-plasma assisted molecular-beam epitaxy. The device structure was grown on a metal-organic chemical vapor deposition GaN-on-sapphire template. The devices displayed repeatable room temperature negative differential resistance with peak tunneling current densities (Jp) between 637 and 930 kA/cm2. Analysis of temperature dependent measurements revealed the presence of severe self-heating effects, which allow strong phonon scattering that deteriorates the electron quantum transport. Finally, a Qualitative Comparison to the same structure grown on a low dislocation density freestanding GaN substrate has shown that sapphire-based templates are a feasible alternative.We report on the design and fabrication of ultrahigh current density GaN/AlN double barrier resonant tunneling diodes grown via rf-plasma assisted molecular-beam epitaxy. The device structure was grown on a metal-organic chemical vapor deposition GaN-on-sapphire template. The devices displayed repeatable room temperature negative differential resistance with peak tunneling current densities (Jp) between 637 and 930 kA/cm2. Analysis of temperature dependent measurements revealed the presence of severe self-heating effects, which allow strong phonon scattering that deteriorates the electron quantum transport. Finally, a Qualitative Comparison to the same structure grown on a low dislocation density freestanding GaN substrate has shown that sapphire-based templates are a feasible alternative.
