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W Shan - One of the best experts on this subject based on the ideXlab platform.
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Band anticrossing in dilute nitrides
Journal of Physics: Condensed Matter, 2004Co-Authors: W Shan, Wladek Walukiewicz, Joel W. Ager, Eugene E. HallerAbstract:Alloying III-V compounds with small amounts of nitrogen leads to dramatic reduction of the Fundamental Band-Gap energy in the resulting dilute nitride alloys. The effect originates from an anti-crossing interaction between the extended conduction-Band states and localized N states. The interaction splits the conduction Band into two nonparabolic subBands. The downward shift of the lower conduction subBand edge is responsible for the N-induced reduction of the Fundamental Band-Gap energy. The changes in the conduction Band structure result in significant increase in electron effective mass and decrease in the electron mobility, and lead to a large enhance of the maximum doping level in GaInNAs doped with group VI donors. In addition, a striking asymmetry in the electrical activation of group IV and group VI donors can be attributed to mutual passivation process through formation of the nearest neighbor group-IV donor nitrogen pairs.
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Pressure dependence of the Fundamental Band-Gap energy of CdSe
Applied Physics Letters, 2004Co-Authors: W Shan, Wladek Walukiewicz, Joel W. Ager, E E HallerAbstract:Pressure-dependent photomodulation spectroscopic studies of the optical transition associated with the Fundamental BandGap of single-crystal bulk CdSe are presented. Photomodulated transmission (PT) measurements were performed at room temperature as a function of applied hydrostatic pressure using the diamond-anvil-cell technique. The sharp, derivative-like PT spectral features corresponding to the Band-Gap transition in CdSe were found to shift linearly toward higher energy with increasing pressure. By examining the pressure dependence of the PT spectra, the pressure coefficient for the direct Band Gap of wurtzite CdSe was determined to be 43.1 meV/GPa. The hydrostatic deformation potential of the Band Gap was found to be −2.3 eV.
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Temperature dependence of the Fundamental Band Gap of InN
Journal of Applied Physics, 2003Co-Authors: Wladek Walukiewicz, W Shan, E E Haller, Joel W. Ager, William J. SchaffAbstract:The Fundamental Band Gap of InN films grown by molecular beam epitaxy have been measured by transmission and photoluminescence spectroscopy as a function of temperature. The Band edge absorption energy and its temperature dependence depend on the doping level. The Band Gap variation and Varshni parameters of InN are compared with other group III nitrides. The energy of the photoluminescence peak is affected by the emission from localized states and cannot be used to determine the Band Gap energy. Based on the results obtained on two samples with distinctly different electron concentrations, the effect of degenerate doping on the optical properties of InN is discussed.
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effects of the narrow Band Gap on the properties of inn
Physical Review B, 2002Co-Authors: W Shan, E E Haller, Junqiao Wu, Wladek Walukiewicz, K M Yu, Joel W. Ager, Hai Lu, William J. SchaffAbstract:Infrared reflection experiments were performed on wurtzite InN films with a range of free-electron concentrations grown by molecular-beam epitaxy. Measurements of the plasma edge frequencies were used to determine electron effective masses. The results show a pronounced increase in the electron effective mass with increasing electron concentration, indicating a nonparabolic conduction Band in InN. We have also found a large Burstein-Moss shift of the Fundamental Band Gap. The observed effects are quantitatively described by the kip interaction within the two-Band Kane model of narrow-Gap semiconductors.
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Effect of nitrogen on the Band structure of III-N-V alloys
Physics and Simulation of Optoelectronic Devices VIII, 2000Co-Authors: W Shan, J. M. Olson, Sarah Kurtz, Wladek Walukiewicz, Joel W. Ager, Daniel J. Friedman, John F. Geisz, Eugene E. Haller, H. P. XinAbstract:Incorporation of a few percent of nitrogen into conventional III-V compounds to form III-N-V alloys such as GaNAs and GaNP leads to a large reduction of the Fundamental Band Gap. We show experimentally and theoretically that the effect originates from an anti-crossing interaction between the extended conduction-Band states and a narrow resonant Band formed by localized N states. The interaction significantly alters the electronic Band structure by splitting the conduction Band into two nonparabolic subBands. The downward shift of the lower conduction subBand edge is responsible for the N-induced reduction of the Fundamental Band-Gap energy.
E E Haller - One of the best experts on this subject based on the ideXlab platform.
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Pressure dependence of the Fundamental Band-Gap energy of CdSe
Applied Physics Letters, 2004Co-Authors: W Shan, Wladek Walukiewicz, Joel W. Ager, E E HallerAbstract:Pressure-dependent photomodulation spectroscopic studies of the optical transition associated with the Fundamental BandGap of single-crystal bulk CdSe are presented. Photomodulated transmission (PT) measurements were performed at room temperature as a function of applied hydrostatic pressure using the diamond-anvil-cell technique. The sharp, derivative-like PT spectral features corresponding to the Band-Gap transition in CdSe were found to shift linearly toward higher energy with increasing pressure. By examining the pressure dependence of the PT spectra, the pressure coefficient for the direct Band Gap of wurtzite CdSe was determined to be 43.1 meV/GPa. The hydrostatic deformation potential of the Band Gap was found to be −2.3 eV.
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Temperature dependence of the Fundamental Band Gap of InN
Journal of Applied Physics, 2003Co-Authors: Wladek Walukiewicz, W Shan, E E Haller, Joel W. Ager, William J. SchaffAbstract:The Fundamental Band Gap of InN films grown by molecular beam epitaxy have been measured by transmission and photoluminescence spectroscopy as a function of temperature. The Band edge absorption energy and its temperature dependence depend on the doping level. The Band Gap variation and Varshni parameters of InN are compared with other group III nitrides. The energy of the photoluminescence peak is affected by the emission from localized states and cannot be used to determine the Band Gap energy. Based on the results obtained on two samples with distinctly different electron concentrations, the effect of degenerate doping on the optical properties of InN is discussed.
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effects of the narrow Band Gap on the properties of inn
Physical Review B, 2002Co-Authors: W Shan, E E Haller, Junqiao Wu, Wladek Walukiewicz, K M Yu, Joel W. Ager, Hai Lu, William J. SchaffAbstract:Infrared reflection experiments were performed on wurtzite InN films with a range of free-electron concentrations grown by molecular-beam epitaxy. Measurements of the plasma edge frequencies were used to determine electron effective masses. The results show a pronounced increase in the electron effective mass with increasing electron concentration, indicating a nonparabolic conduction Band in InN. We have also found a large Burstein-Moss shift of the Fundamental Band Gap. The observed effects are quantitatively described by the kip interaction within the two-Band Kane model of narrow-Gap semiconductors.
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unusual properties of the Fundamental Band Gap of inn
Applied Physics Letters, 2002Co-Authors: Junqiao Wu, E E Haller, William J. Schaff, Wladek Walukiewicz, Yoshiki Saito, K M Yu, Joel W. Ager, Hai Lu, Yasushi NanishiAbstract:The optical properties of wurtzite-structured InN grown on sapphire substrates by molecular-beam epitaxy have been characterized by optical absorption, photoluminescence, and photomodulated reflectance techniques. These three characterization techniques show an energy Gap for InN between 0.7 and 0.8 eV, much lower than the commonly accepted value of 1.9 eV. The photoluminescence peak energy is found to be sensitive to the free-electron concentration of the sample. The peak energy exhibits very weak hydrostatic pressure dependence, and a small, anomalous blueshift with increasing temperature.
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Nature of the Fundamental Band Gap in GaNxP1−x alloys
Applied Physics Letters, 2000Co-Authors: W Shan, E E Haller, Wladek Walukiewicz, Joel W. Ager, H. P. XinAbstract:The optical properties of GaNxP1−x alloys (0.007⩽x⩽0.031) grown by gas-source molecular-beam epitaxy have been studied. An absorption edge appears in GaNxP1−x at energy below the indirect ΓV–XC transition in Gap, and the absorption edge shifts to lower energy with increasing N concentration. Strong photomodulation signals associated with the absorption edges in GaNxP1−x indicate that a direct Fundamental optical transition is taking place, revealing that the Fundamental Band Gap has changed from indirect to direct. This N-induced transformation from indirect to direct Band Gap is explained in terms of an interaction between the highly localized nitrogen states and the extended states at the Γ conduction-Band minimum.
Wladek Walukiewicz - One of the best experts on this subject based on the ideXlab platform.
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Band anticrossing in dilute nitrides
Journal of Physics: Condensed Matter, 2004Co-Authors: W Shan, Wladek Walukiewicz, Joel W. Ager, Eugene E. HallerAbstract:Alloying III-V compounds with small amounts of nitrogen leads to dramatic reduction of the Fundamental Band-Gap energy in the resulting dilute nitride alloys. The effect originates from an anti-crossing interaction between the extended conduction-Band states and localized N states. The interaction splits the conduction Band into two nonparabolic subBands. The downward shift of the lower conduction subBand edge is responsible for the N-induced reduction of the Fundamental Band-Gap energy. The changes in the conduction Band structure result in significant increase in electron effective mass and decrease in the electron mobility, and lead to a large enhance of the maximum doping level in GaInNAs doped with group VI donors. In addition, a striking asymmetry in the electrical activation of group IV and group VI donors can be attributed to mutual passivation process through formation of the nearest neighbor group-IV donor nitrogen pairs.
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Pressure dependence of the Fundamental Band-Gap energy of CdSe
Applied Physics Letters, 2004Co-Authors: W Shan, Wladek Walukiewicz, Joel W. Ager, E E HallerAbstract:Pressure-dependent photomodulation spectroscopic studies of the optical transition associated with the Fundamental BandGap of single-crystal bulk CdSe are presented. Photomodulated transmission (PT) measurements were performed at room temperature as a function of applied hydrostatic pressure using the diamond-anvil-cell technique. The sharp, derivative-like PT spectral features corresponding to the Band-Gap transition in CdSe were found to shift linearly toward higher energy with increasing pressure. By examining the pressure dependence of the PT spectra, the pressure coefficient for the direct Band Gap of wurtzite CdSe was determined to be 43.1 meV/GPa. The hydrostatic deformation potential of the Band Gap was found to be −2.3 eV.
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Temperature dependence of the Fundamental Band Gap of InN
Journal of Applied Physics, 2003Co-Authors: Wladek Walukiewicz, W Shan, E E Haller, Joel W. Ager, William J. SchaffAbstract:The Fundamental Band Gap of InN films grown by molecular beam epitaxy have been measured by transmission and photoluminescence spectroscopy as a function of temperature. The Band edge absorption energy and its temperature dependence depend on the doping level. The Band Gap variation and Varshni parameters of InN are compared with other group III nitrides. The energy of the photoluminescence peak is affected by the emission from localized states and cannot be used to determine the Band Gap energy. Based on the results obtained on two samples with distinctly different electron concentrations, the effect of degenerate doping on the optical properties of InN is discussed.
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effects of the narrow Band Gap on the properties of inn
Physical Review B, 2002Co-Authors: W Shan, E E Haller, Junqiao Wu, Wladek Walukiewicz, K M Yu, Joel W. Ager, Hai Lu, William J. SchaffAbstract:Infrared reflection experiments were performed on wurtzite InN films with a range of free-electron concentrations grown by molecular-beam epitaxy. Measurements of the plasma edge frequencies were used to determine electron effective masses. The results show a pronounced increase in the electron effective mass with increasing electron concentration, indicating a nonparabolic conduction Band in InN. We have also found a large Burstein-Moss shift of the Fundamental Band Gap. The observed effects are quantitatively described by the kip interaction within the two-Band Kane model of narrow-Gap semiconductors.
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unusual properties of the Fundamental Band Gap of inn
Applied Physics Letters, 2002Co-Authors: Junqiao Wu, E E Haller, William J. Schaff, Wladek Walukiewicz, Yoshiki Saito, K M Yu, Joel W. Ager, Hai Lu, Yasushi NanishiAbstract:The optical properties of wurtzite-structured InN grown on sapphire substrates by molecular-beam epitaxy have been characterized by optical absorption, photoluminescence, and photomodulated reflectance techniques. These three characterization techniques show an energy Gap for InN between 0.7 and 0.8 eV, much lower than the commonly accepted value of 1.9 eV. The photoluminescence peak energy is found to be sensitive to the free-electron concentration of the sample. The peak energy exhibits very weak hydrostatic pressure dependence, and a small, anomalous blueshift with increasing temperature.
Joel W. Ager - One of the best experts on this subject based on the ideXlab platform.
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Band anticrossing in dilute nitrides
Journal of Physics: Condensed Matter, 2004Co-Authors: W Shan, Wladek Walukiewicz, Joel W. Ager, Eugene E. HallerAbstract:Alloying III-V compounds with small amounts of nitrogen leads to dramatic reduction of the Fundamental Band-Gap energy in the resulting dilute nitride alloys. The effect originates from an anti-crossing interaction between the extended conduction-Band states and localized N states. The interaction splits the conduction Band into two nonparabolic subBands. The downward shift of the lower conduction subBand edge is responsible for the N-induced reduction of the Fundamental Band-Gap energy. The changes in the conduction Band structure result in significant increase in electron effective mass and decrease in the electron mobility, and lead to a large enhance of the maximum doping level in GaInNAs doped with group VI donors. In addition, a striking asymmetry in the electrical activation of group IV and group VI donors can be attributed to mutual passivation process through formation of the nearest neighbor group-IV donor nitrogen pairs.
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Pressure dependence of the Fundamental Band-Gap energy of CdSe
Applied Physics Letters, 2004Co-Authors: W Shan, Wladek Walukiewicz, Joel W. Ager, E E HallerAbstract:Pressure-dependent photomodulation spectroscopic studies of the optical transition associated with the Fundamental BandGap of single-crystal bulk CdSe are presented. Photomodulated transmission (PT) measurements were performed at room temperature as a function of applied hydrostatic pressure using the diamond-anvil-cell technique. The sharp, derivative-like PT spectral features corresponding to the Band-Gap transition in CdSe were found to shift linearly toward higher energy with increasing pressure. By examining the pressure dependence of the PT spectra, the pressure coefficient for the direct Band Gap of wurtzite CdSe was determined to be 43.1 meV/GPa. The hydrostatic deformation potential of the Band Gap was found to be −2.3 eV.
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Temperature dependence of the Fundamental Band Gap of InN
Journal of Applied Physics, 2003Co-Authors: Wladek Walukiewicz, W Shan, E E Haller, Joel W. Ager, William J. SchaffAbstract:The Fundamental Band Gap of InN films grown by molecular beam epitaxy have been measured by transmission and photoluminescence spectroscopy as a function of temperature. The Band edge absorption energy and its temperature dependence depend on the doping level. The Band Gap variation and Varshni parameters of InN are compared with other group III nitrides. The energy of the photoluminescence peak is affected by the emission from localized states and cannot be used to determine the Band Gap energy. Based on the results obtained on two samples with distinctly different electron concentrations, the effect of degenerate doping on the optical properties of InN is discussed.
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effects of the narrow Band Gap on the properties of inn
Physical Review B, 2002Co-Authors: W Shan, E E Haller, Junqiao Wu, Wladek Walukiewicz, K M Yu, Joel W. Ager, Hai Lu, William J. SchaffAbstract:Infrared reflection experiments were performed on wurtzite InN films with a range of free-electron concentrations grown by molecular-beam epitaxy. Measurements of the plasma edge frequencies were used to determine electron effective masses. The results show a pronounced increase in the electron effective mass with increasing electron concentration, indicating a nonparabolic conduction Band in InN. We have also found a large Burstein-Moss shift of the Fundamental Band Gap. The observed effects are quantitatively described by the kip interaction within the two-Band Kane model of narrow-Gap semiconductors.
-
unusual properties of the Fundamental Band Gap of inn
Applied Physics Letters, 2002Co-Authors: Junqiao Wu, E E Haller, William J. Schaff, Wladek Walukiewicz, Yoshiki Saito, K M Yu, Joel W. Ager, Hai Lu, Yasushi NanishiAbstract:The optical properties of wurtzite-structured InN grown on sapphire substrates by molecular-beam epitaxy have been characterized by optical absorption, photoluminescence, and photomodulated reflectance techniques. These three characterization techniques show an energy Gap for InN between 0.7 and 0.8 eV, much lower than the commonly accepted value of 1.9 eV. The photoluminescence peak energy is found to be sensitive to the free-electron concentration of the sample. The peak energy exhibits very weak hydrostatic pressure dependence, and a small, anomalous blueshift with increasing temperature.
Hyoyeol Park - One of the best experts on this subject based on the ideXlab platform.
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temperature dependence of the Fundamental Band Gap energy of cd1 xcoxte single crystals
Solid State Communications, 1998Co-Authors: Hyekyeong Kim, Gwangsoo Jeen, Seongtae Park, Younghun Hwang, Hyoyeol ParkAbstract:Abstract Cd 1− x Co x Te single crystals were grown by the vertical Bridgman method. The optical Band Gap energy of Cd 1− x Co x Te( x =0, 0.001, 0.004, 0.008) were obtained as a function of temperature (12 ∼ 300K) and cobalt composition x . The temperature variation of the energy Gap could be well fitted by the empirical Varshni relation. The temperature coefficient at low temperature decreased with x , but was nearly constant at high temperature. The Band Gap energy decreased linearly with composition.
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Temperature dependence of the Fundamental Band Gap energy of Cd1−xCoxTe single crystals
Solid State Communications, 1998Co-Authors: Hyekyeong Kim, Gwangsoo Jeen, Seongtae Park, Younghun Hwang, Hyoyeol ParkAbstract:Abstract Cd 1− x Co x Te single crystals were grown by the vertical Bridgman method. The optical Band Gap energy of Cd 1− x Co x Te( x =0, 0.001, 0.004, 0.008) were obtained as a function of temperature (12 ∼ 300K) and cobalt composition x . The temperature variation of the energy Gap could be well fitted by the empirical Varshni relation. The temperature coefficient at low temperature decreased with x , but was nearly constant at high temperature. The Band Gap energy decreased linearly with composition.
