The Experts below are selected from a list of 11376 Experts worldwide ranked by ideXlab platform
James S Speck - One of the best experts on this subject based on the ideXlab platform.
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measurement of polarization charge and conduction band offset at inxga1 xn gan heterojunction interfaces
Applied Physics Letters, 2004Co-Authors: H Zhang, E J Miller, C Poblenz, James S SpeckAbstract:The spontaneous and piezoelectric polarization fields in group-III Nitride Semiconductors lead to the presence of large electrostatic sheet charge densities at Nitride Semiconductor heterojunction interfaces. Precise quantitative knowledge of these polarization-induced charge densities and of the band-edge discontinuities at Nitride heterojunction interfaces is therefore essential in Nitride Semiconductor device design and analysis. We have used capacitance–voltage profiling to measure the conduction-band offset and polarization charge density at InxGa1−xN/GaN heterojunction interfaces with x=0.054 and x=0.09. We obtain conduction-band offsets ΔEC=0.09±0.07 eV for x=0.054 and ΔEC=0.22±0.05 eV for x=0.09, corresponding to an averaged conduction-to-valence-band offset ratio ΔEC:ΔEV of 58:42. Our measurements yield polarization charge densities of (1.80±0.32)×1012 e/cm2 for x=0.054 and (4.38±0.36)×1012 e/cm2 for x=0.09. These values are smaller than those predicted by recent theoretical calculations, but in ...
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measurement of polarization charge and conduction band offset at inxga1 xn gan heterojunction interfaces
Applied Physics Letters, 2004Co-Authors: H Zhang, E J Miller, C Poblenz, James S SpeckAbstract:The spontaneous and piezoelectric polarization fields in group-III Nitride Semiconductors lead to the presence of large electrostatic sheet charge densities at Nitride Semiconductor heterojunction interfaces. Precise quantitative knowledge of these polarization-induced charge densities and of the band-edge discontinuities at Nitride heterojunction interfaces is therefore essential in Nitride Semiconductor device design and analysis. We have used capacitance–voltage profiling to measure the conduction-band offset and polarization charge density at InxGa1−xN/GaN heterojunction interfaces with x=0.054 and x=0.09. We obtain conduction-band offsets ΔEC=0.09±0.07 eV for x=0.054 and ΔEC=0.22±0.05 eV for x=0.09, corresponding to an averaged conduction-to-valence-band offset ratio ΔEC:ΔEV of 58:42. Our measurements yield polarization charge densities of (1.80±0.32)×1012 e/cm2 for x=0.054 and (4.38±0.36)×1012 e/cm2 for x=0.09. These values are smaller than those predicted by recent theoretical calculations, but in good agreement with values inferred from a number of optical experiments.
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blue gan based light emitting diodes grown by molecular beam epitaxy with external quantum efficiency greater than 1 5
Applied Physics Letters, 2004Co-Authors: P Waltereit, C Poblenz, James S Speck, Steven P Denbaars, Hitoshi Sato, D S Green, Jay S Brown, Melvin Mclaurin, Thomas M Katona, J H LiangAbstract:We have grown blue (480 nm) Nitride Semiconductor light emitting diodes (LEDs) by plasma-assisted molecular beam epitaxy (MBE) on GaN templates. Packaged devices exhibited output powers up to 0.87 mW at 20 mA forward current. The corresponding external quantum efficiency was 1.68%. Utilizing a combination of direct current (dc) and pulsed electroluminescence measurements it has been demonstrated that at low (<20 mA) dc conditions the emission from these devices is governed by the combined effects of bandfilling and screening of electrostatic fields. However, at larger currents device heating dominates the emission properties.
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realization of wide electron slabs by polarization bulk doping in graded iii v Nitride Semiconductor alloys
Applied Physics Letters, 2002Co-Authors: Debdeep Jena, James S Speck, D S Green, S Heikman, D Buttari, R Coffie, Huili Xing, Stacia Keller, S P Denbaars, U K MishraAbstract:We present the concept and experimental realization of polarization-induced bulk electron doping in III–V Nitride Semiconductors. By exploiting the large polarization charges in the III–V Nitrides, we are able to create wide slabs of high-density mobile electrons without introducing shallow donors. Transport measurements reveal the superior properties of the polarization-doped electron distributions than comparable shallow donor-doped structures, especially at low temperatures due to the removal of ionized impurity scattering. Such polarization-induced three-dimensional electron slabs can be utilized in a variety of device structures owing to their high conductivity and continuously changing energy gap.
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realization of wide electron slabs by polarization bulk doping in graded iii v Nitride Semiconductor alloys
arXiv: Condensed Matter, 2002Co-Authors: Debdeep Jena, James S Speck, D S Green, S Heikman, R Coffie, Huili Xing, Stacia Keller, S P Denbaars, Ilan B Yaacov, U K MishraAbstract:We present the concept and experimental realization of polarization-induced bulk electron doping in III-V Nitride Semiconductors. By exploiting the large polarization charges in the III-V Nitrides, we are able to create wide slabs of high density mobile electrons without introducing shallow donors. Transport measurements reveal the superior properties of the polarization doped electron distributions than comparable shallow donor doped structures. The technique is readily employed for creating highly conductive layers in many device structures.
C Poblenz - One of the best experts on this subject based on the ideXlab platform.
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measurement of polarization charge and conduction band offset at inxga1 xn gan heterojunction interfaces
Applied Physics Letters, 2004Co-Authors: H Zhang, E J Miller, C Poblenz, James S SpeckAbstract:The spontaneous and piezoelectric polarization fields in group-III Nitride Semiconductors lead to the presence of large electrostatic sheet charge densities at Nitride Semiconductor heterojunction interfaces. Precise quantitative knowledge of these polarization-induced charge densities and of the band-edge discontinuities at Nitride heterojunction interfaces is therefore essential in Nitride Semiconductor device design and analysis. We have used capacitance–voltage profiling to measure the conduction-band offset and polarization charge density at InxGa1−xN/GaN heterojunction interfaces with x=0.054 and x=0.09. We obtain conduction-band offsets ΔEC=0.09±0.07 eV for x=0.054 and ΔEC=0.22±0.05 eV for x=0.09, corresponding to an averaged conduction-to-valence-band offset ratio ΔEC:ΔEV of 58:42. Our measurements yield polarization charge densities of (1.80±0.32)×1012 e/cm2 for x=0.054 and (4.38±0.36)×1012 e/cm2 for x=0.09. These values are smaller than those predicted by recent theoretical calculations, but in ...
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measurement of polarization charge and conduction band offset at inxga1 xn gan heterojunction interfaces
Applied Physics Letters, 2004Co-Authors: H Zhang, E J Miller, C Poblenz, James S SpeckAbstract:The spontaneous and piezoelectric polarization fields in group-III Nitride Semiconductors lead to the presence of large electrostatic sheet charge densities at Nitride Semiconductor heterojunction interfaces. Precise quantitative knowledge of these polarization-induced charge densities and of the band-edge discontinuities at Nitride heterojunction interfaces is therefore essential in Nitride Semiconductor device design and analysis. We have used capacitance–voltage profiling to measure the conduction-band offset and polarization charge density at InxGa1−xN/GaN heterojunction interfaces with x=0.054 and x=0.09. We obtain conduction-band offsets ΔEC=0.09±0.07 eV for x=0.054 and ΔEC=0.22±0.05 eV for x=0.09, corresponding to an averaged conduction-to-valence-band offset ratio ΔEC:ΔEV of 58:42. Our measurements yield polarization charge densities of (1.80±0.32)×1012 e/cm2 for x=0.054 and (4.38±0.36)×1012 e/cm2 for x=0.09. These values are smaller than those predicted by recent theoretical calculations, but in good agreement with values inferred from a number of optical experiments.
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blue gan based light emitting diodes grown by molecular beam epitaxy with external quantum efficiency greater than 1 5
Applied Physics Letters, 2004Co-Authors: P Waltereit, C Poblenz, James S Speck, Steven P Denbaars, Hitoshi Sato, D S Green, Jay S Brown, Melvin Mclaurin, Thomas M Katona, J H LiangAbstract:We have grown blue (480 nm) Nitride Semiconductor light emitting diodes (LEDs) by plasma-assisted molecular beam epitaxy (MBE) on GaN templates. Packaged devices exhibited output powers up to 0.87 mW at 20 mA forward current. The corresponding external quantum efficiency was 1.68%. Utilizing a combination of direct current (dc) and pulsed electroluminescence measurements it has been demonstrated that at low (<20 mA) dc conditions the emission from these devices is governed by the combined effects of bandfilling and screening of electrostatic fields. However, at larger currents device heating dominates the emission properties.
H Zhang - One of the best experts on this subject based on the ideXlab platform.
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measurement of polarization charge and conduction band offset at inxga1 xn gan heterojunction interfaces
Applied Physics Letters, 2004Co-Authors: H Zhang, E J Miller, C Poblenz, James S SpeckAbstract:The spontaneous and piezoelectric polarization fields in group-III Nitride Semiconductors lead to the presence of large electrostatic sheet charge densities at Nitride Semiconductor heterojunction interfaces. Precise quantitative knowledge of these polarization-induced charge densities and of the band-edge discontinuities at Nitride heterojunction interfaces is therefore essential in Nitride Semiconductor device design and analysis. We have used capacitance–voltage profiling to measure the conduction-band offset and polarization charge density at InxGa1−xN/GaN heterojunction interfaces with x=0.054 and x=0.09. We obtain conduction-band offsets ΔEC=0.09±0.07 eV for x=0.054 and ΔEC=0.22±0.05 eV for x=0.09, corresponding to an averaged conduction-to-valence-band offset ratio ΔEC:ΔEV of 58:42. Our measurements yield polarization charge densities of (1.80±0.32)×1012 e/cm2 for x=0.054 and (4.38±0.36)×1012 e/cm2 for x=0.09. These values are smaller than those predicted by recent theoretical calculations, but in ...
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measurement of polarization charge and conduction band offset at inxga1 xn gan heterojunction interfaces
Applied Physics Letters, 2004Co-Authors: H Zhang, E J Miller, C Poblenz, James S SpeckAbstract:The spontaneous and piezoelectric polarization fields in group-III Nitride Semiconductors lead to the presence of large electrostatic sheet charge densities at Nitride Semiconductor heterojunction interfaces. Precise quantitative knowledge of these polarization-induced charge densities and of the band-edge discontinuities at Nitride heterojunction interfaces is therefore essential in Nitride Semiconductor device design and analysis. We have used capacitance–voltage profiling to measure the conduction-band offset and polarization charge density at InxGa1−xN/GaN heterojunction interfaces with x=0.054 and x=0.09. We obtain conduction-band offsets ΔEC=0.09±0.07 eV for x=0.054 and ΔEC=0.22±0.05 eV for x=0.09, corresponding to an averaged conduction-to-valence-band offset ratio ΔEC:ΔEV of 58:42. Our measurements yield polarization charge densities of (1.80±0.32)×1012 e/cm2 for x=0.054 and (4.38±0.36)×1012 e/cm2 for x=0.09. These values are smaller than those predicted by recent theoretical calculations, but in good agreement with values inferred from a number of optical experiments.
Marisol Martingonzalez - One of the best experts on this subject based on the ideXlab platform.
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high mobility and high thermoelectric power factor in epitaxial scn thin films deposited with plasma assisted molecular beam epitaxy
Applied Physics Letters, 2020Co-Authors: Dheemahi Rao, Bidesh Biswas, Eduardo Flores, Abhijit Chatterjee, Magnus Garbrecht, Yee Rui Koh, Vijay Bhatia, Ashalatha Indiradevi Kamalasanan Pillai, Patrick E Hopkins, Marisol MartingonzalezAbstract:Scandium Nitride (ScN) is an emerging rock salt III-Nitride Semiconductor and has attracted significant interest in recent years for its potential thermoelectric applications as a substrate for high-quality epitaxial GaN growth and as a semiconducting component for epitaxial single-crystalline metal/Semiconductor superlattices for thermionic energy conversion. Solid-solution alloys of ScN with traditional III-Nitrides such as AlxSc1−xN have demonstrated piezoelectric and ferroelectric properties and are actively researched for device applications. While most of these exciting developments in ScN research have employed films deposited using low-vacuum methods such as magnetron sputtering and physical and chemical vapor depositions for thermoelectric applications and Schottky barrier-based thermionic energy conversion, it is necessary and important to avoid impurities, tune the carrier concentrations, and achieve high-mobility in epitaxial films. Here, we report the high-mobility and high-thermoelectric power factor in epitaxial ScN thin films deposited on MgO substrates by plasma-assisted molecular beam epitaxy. Microstructural characterization shows epitaxial 002 oriented ScN film growth on MgO (001) substrates. Electrical measurements demonstrated a high room-temperature mobility of 127 cm2/V s and temperature-dependent mobility in the temperature range of 50–400 K that is dominated by dislocation and grain boundary scattering. High mobility in ScN films leads to large Seebeck coefficients (−175 μV/K at 950 K) and, along with a moderately high electrical conductivity, a large thermoelectric power factor (2.3 × 10−3 W/m-K2 at 500 K) was achieved, which makes ScN a promising candidate for thermoelectric applications. The thermal conductivity of the films, however, was found to be a bit large, which resulted in a maximum figure-of-merit of 0.17 at 500 K.
E J Miller - One of the best experts on this subject based on the ideXlab platform.
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measurement of polarization charge and conduction band offset at inxga1 xn gan heterojunction interfaces
Applied Physics Letters, 2004Co-Authors: H Zhang, E J Miller, C Poblenz, James S SpeckAbstract:The spontaneous and piezoelectric polarization fields in group-III Nitride Semiconductors lead to the presence of large electrostatic sheet charge densities at Nitride Semiconductor heterojunction interfaces. Precise quantitative knowledge of these polarization-induced charge densities and of the band-edge discontinuities at Nitride heterojunction interfaces is therefore essential in Nitride Semiconductor device design and analysis. We have used capacitance–voltage profiling to measure the conduction-band offset and polarization charge density at InxGa1−xN/GaN heterojunction interfaces with x=0.054 and x=0.09. We obtain conduction-band offsets ΔEC=0.09±0.07 eV for x=0.054 and ΔEC=0.22±0.05 eV for x=0.09, corresponding to an averaged conduction-to-valence-band offset ratio ΔEC:ΔEV of 58:42. Our measurements yield polarization charge densities of (1.80±0.32)×1012 e/cm2 for x=0.054 and (4.38±0.36)×1012 e/cm2 for x=0.09. These values are smaller than those predicted by recent theoretical calculations, but in ...
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measurement of polarization charge and conduction band offset at inxga1 xn gan heterojunction interfaces
Applied Physics Letters, 2004Co-Authors: H Zhang, E J Miller, C Poblenz, James S SpeckAbstract:The spontaneous and piezoelectric polarization fields in group-III Nitride Semiconductors lead to the presence of large electrostatic sheet charge densities at Nitride Semiconductor heterojunction interfaces. Precise quantitative knowledge of these polarization-induced charge densities and of the band-edge discontinuities at Nitride heterojunction interfaces is therefore essential in Nitride Semiconductor device design and analysis. We have used capacitance–voltage profiling to measure the conduction-band offset and polarization charge density at InxGa1−xN/GaN heterojunction interfaces with x=0.054 and x=0.09. We obtain conduction-band offsets ΔEC=0.09±0.07 eV for x=0.054 and ΔEC=0.22±0.05 eV for x=0.09, corresponding to an averaged conduction-to-valence-band offset ratio ΔEC:ΔEV of 58:42. Our measurements yield polarization charge densities of (1.80±0.32)×1012 e/cm2 for x=0.054 and (4.38±0.36)×1012 e/cm2 for x=0.09. These values are smaller than those predicted by recent theoretical calculations, but in good agreement with values inferred from a number of optical experiments.