The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
A Y Polyakov - One of the best experts on this subject based on the ideXlab platform.
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hydrogen plasma treatment of β ga2o3 changes in electrical properties and Deep Trap spectra
Applied Physics Letters, 2019Co-Authors: A Y Polyakov, Inhwan Lee, N B Smirnov, I V Shchemerov, E B Yakimov, A V Chernykh, A I Kochkova, A A Vasilev, F RenAbstract:The effects of hydrogen plasma treatment of β-Ga2O3 grown by halide vapor phase epitaxy and doped with Si are reported. Samples subjected to H plasma exposure at 330 °C developed a wide (∼2.5 μm-thick) region near the surface, depleted of electrons at room temperature. The thickness of the layer is in reasonable agreement with the estimated hydrogen penetration depth in β-Ga2O3 based on previous deuterium profiling experiments. Admittance spectroscopy and photoinduced current transient spectroscopy measurements place the Fermi level pinning position in the H treated film near Ec-1.05 eV. Annealing at 450 °C decreased the thickness of the depletion layer to 1.3 μm at room temperature and moved the Fermi level pinning position to Ec-0.8 eV. Further annealing at 550 °C almost restored the starting shallow donor concentration and the spectra of Deep Traps dominated by Ec-0.8 eV and Ec-1.05 eV observed before hydrogen treatment. It is suggested that hydrogen plasma exposure produces surface damage in the near-surface region and passivates or compensates shallow donors.The effects of hydrogen plasma treatment of β-Ga2O3 grown by halide vapor phase epitaxy and doped with Si are reported. Samples subjected to H plasma exposure at 330 °C developed a wide (∼2.5 μm-thick) region near the surface, depleted of electrons at room temperature. The thickness of the layer is in reasonable agreement with the estimated hydrogen penetration depth in β-Ga2O3 based on previous deuterium profiling experiments. Admittance spectroscopy and photoinduced current transient spectroscopy measurements place the Fermi level pinning position in the H treated film near Ec-1.05 eV. Annealing at 450 °C decreased the thickness of the depletion layer to 1.3 μm at room temperature and moved the Fermi level pinning position to Ec-0.8 eV. Further annealing at 550 °C almost restored the starting shallow donor concentration and the spectra of Deep Traps dominated by Ec-0.8 eV and Ec-1.05 eV observed before hydrogen treatment. It is suggested that hydrogen plasma exposure produces surface damage in the near-...
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Deep Trap analysis in green light emitting diodes problems and solutions
Journal of Applied Physics, 2019Co-Authors: A Y Polyakov, Inhwan Lee, N B Smirnov, I V Shchemerov, N M Shmidt, E I Shabunina, N A Talnishnih, L A Alexanyan, S A Tarelkin, S J PeartonAbstract:Some green light emitting diodes (LEDs) based on GaN/InGaN multiquantum-well (MQW) structures exhibit strong frequency and temperature dependence of capacitance and prominent changes in capacitance–voltage profiles with temperature that make it difficult to obtain reliable Deep level transient spectroscopy (DLTS) measurements. DLTS performed at low probing signal frequency and with constant capacitance between the measurements by controlling applied bias mitigates these issues. This allows measurement of Deep electron and hole Traps in specific quantum wells (QWs) in the MQW structure. The dominant electron and hole Traps detected have levels near Ec− (0.45–0.5) eV and Ev+ (0.6–0.63) eV. Their density increases significantly after aging for a long period (2120 h) at high driving current and elevated temperature. The reason for the observed anomalies in DLTS spectra of these green LEDs is the high density of states in the QWs with activation energies near 0.08, 0.12–0.14, and 0.3 eV, detected in admittance spectra, and, for the 0.08 eV and 0.3 eV, these states are likely related to defects.
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Deep Trap spectra of sn doped α ga 2 o 3 grown by halide vapor phase epitaxy on sapphire
APL Materials, 2019Co-Authors: A Y Polyakov, N B Smirnov, I V Shchemerov, E B Yakimov, A V Chernykh, V I Nikolaev, S I Stepanov, A I Pechnikov, K D ShcherbachevAbstract:Epitaxial layers of α-Ga2O3 with different Sn doping levels were grown by halide vapor phase epitaxy on sapphire. The films had shallow donor concentrations ranging from 1017 to 4.8 × 1019 cm−3. Deep level transient spectroscopy of the lowest doped samples revealed dominant A Traps with level Ec − 0.6 eV and B Traps near Ec − 1.1 eV. With increasing shallow donor concentration, the density of the A Traps increased, and new Traps C (Ec − 0.85 eV) and D (Ec − 0.23 eV) emerged. Photocapacitance spectra showed the presence of Deep Traps with optical ionization energy of ∼2 and 2.7 eV and prominent persistent photocapacitance at low temperature, surviving heating to temperatures above room temperature. The diffusion length of nonequilibrium charge carriers was 0.15 µm, and microcathodoluminescence spectra showed peaks in the range 339–540 nm, but no band-edge emission.Epitaxial layers of α-Ga2O3 with different Sn doping levels were grown by halide vapor phase epitaxy on sapphire. The films had shallow donor concentrations ranging from 1017 to 4.8 × 1019 cm−3. Deep level transient spectroscopy of the lowest doped samples revealed dominant A Traps with level Ec − 0.6 eV and B Traps near Ec − 1.1 eV. With increasing shallow donor concentration, the density of the A Traps increased, and new Traps C (Ec − 0.85 eV) and D (Ec − 0.23 eV) emerged. Photocapacitance spectra showed the presence of Deep Traps with optical ionization energy of ∼2 and 2.7 eV and prominent persistent photocapacitance at low temperature, surviving heating to temperatures above room temperature. The diffusion length of nonequilibrium charge carriers was 0.15 µm, and microcathodoluminescence spectra showed peaks in the range 339–540 nm, but no band-edge emission.
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Trap states in multication mesoscopic perovskite solar cells a Deep levels transient spectroscopy investigation
Applied Physics Letters, 2018Co-Authors: A Y Polyakov, N B Smirnov, I V Shchemerov, D Saranin, S I Didenko, Denis Kuznetsov, Antonio Agresti, Sara Pescetelli, Fabio Matteocci, A Di CarloAbstract:This work presents a study of Trap levels in a mesoscopic multication lead halide perovskite solar cell structure. The investigation is performed by combining capacitance measurements, admittance measurements, Deep Level Transient Spectroscopy (DLTS), and Optical DLTS. We found a donor level with an energy of 0.2 eV below the conduction band of perovskite. The donor density reaches a concentration of 1018 cm−3 in the accumulation region present at the interface between the perovskite and transporting layers. Other two Deep Trap levels are found with energies of 0.57 eV and 0.74 eV. The first level is related to a hole Trap while the second one to an electron Trap.
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defects responsible for lifetime degradation in electron irradiated n gan grown by hydride vapor phase epitaxy
Applied Physics Letters, 2017Co-Authors: Inhwan Lee, A Y Polyakov, N B Smirnov, I V Shchemerov, E B Yakimov, S A Tarelkin, S I Didenko, K I Tapero, R A ZinovyevAbstract:The effects of room temperature 6 MeV electron irradiation on the donor concentration, Deep Trap spectra, and diffusion lengths of nonequilibrium charge carriers were studied for undoped n-GaN grown by hydride vapor phase epitaxy. Changes in these parameters begin at a threshold electron fluence of 5 × 1015 cm−2. The diffusion lengths after this fluence decrease by a factor of 3, accompanied by a drastic increase in the density of Deep electron Traps with the level near Ec – 1 eV. There is a strong correlation between the changes in the density of these Traps and the diffusion length of irradiated n-GaN, indicating that these centers control the lifetime in radiation damaged n-GaN. This is in sharp contrast to the starting material, where the lifetimes are controlled by other Deep electron Traps at Ec – 0.56 eV. The concentration of the latter is not strongly affected by high energy electron irradiation.
Rongjun Xie - One of the best experts on this subject based on the ideXlab platform.
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tailoring Trap depth and emission wavelength in y3al5 xgaxo12 ce3 v3 phosphor in glass films for optical information storage
ACS Applied Materials & Interfaces, 2018Co-Authors: Yixi Zhuang, Peng Zheng, Tianliang Zhou, Jumpei Ueda, Setsuhisa Tanabe, Le Wang, Rongjun XieAbstract:Deep-Trap persistent luminescent materials, due to their exceptional ability of energy storage and controllable photon release under external stimulation, have attracted considerable attention in the field of optical information storage. Currently, the lack of suitable materials is still the bottleneck that restrains their practical applications. Herein, we successfully synthesized a series of Deep-Trap persistent luminescent materials Y3Al5–xGaxO12:Ce3+,V3+ (x = 0–3) with a garnet structure and developed novel phosphor-in-glass (PiG) films containing these phosphors. The synthesized PiG films exhibited sufficiently Deep Traps, narrow Trap depth distributions, high Trap density, high quantum efficiency, and excellent chemical stability, which solved the problem of chemical stability at high temperatures in the reported phosphor-in-silicone films. Moreover, the Trap depth in the phosphors and PiG films could be tailored from 1.2 to 1.6 eV, thanks to the bandgap engineering effect, and the emission color wa...
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Trap depth engineering of srsi2o2n2 ln2 ln3 ln2 yb eu ln3 dy ho er persistent luminescence materials for information storage applications
ACS Applied Materials & Interfaces, 2018Co-Authors: Yixi Zhuang, Tianliang Zhou, Le Wang, Wenwei Chen, Takashi Takeda, Naoto Hirosaki, Rongjun XieAbstract:Deep-Trap persistent luminescence materials exhibit unique properties of energy storage and controllable photon release under additional stimulation, allowing for both wavelength and intensity multiplexing to realize high-capacity storage in the next-generation information storage system. However, the lack of suitable persistent luminescence materials with Deep Traps is the bottleneck of such storage technologies. In this study, we successfully developed a series of novel Deep-Trap persistent luminescence materials in the Ln2+/Ln3+-doped SrSi2O2N2 system (Ln2+ = Yb, Eu; Ln3+ = Dy, Ho, Er) by applying the strategy of Trap depth engineering. Interestingly, the Trap depth can be tailored by selecting different codopants, and it monotonically increases from 0.90 to 1.18 eV in the order of Er, Ho, and Dy. This is well explained by the energy levels indicated in the host-referred binding energy scheme. The orange-red-emitting SrSi2O2N2:Yb,Dy and green-emitting SrSi2O2N2:Eu,Dy phosphors are demonstrated to be go...
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Tailoring Trap Depth and Emission Wavelength in Y3Al5–xGaxO12:Ce3+,V3+ Phosphor-in-Glass Films for Optical Information Storage
2018Co-Authors: Yixi Zhuang, Peng Zheng, Tianliang Zhou, Jumpei Ueda, Setsuhisa Tanabe, Le Wang, Rongjun XieAbstract:Deep-Trap persistent luminescent materials, due to their exceptional ability of energy storage and controllable photon release under external stimulation, have attracted considerable attention in the field of optical information storage. Currently, the lack of suitable materials is still the bottleneck that restrains their practical applications. Herein, we successfully synthesized a series of Deep-Trap persistent luminescent materials Y3Al5–xGaxO12:Ce3+,V3+ (x = 0–3) with a garnet structure and developed novel phosphor-in-glass (PiG) films containing these phosphors. The synthesized PiG films exhibited sufficiently Deep Traps, narrow Trap depth distributions, high Trap density, high quantum efficiency, and excellent chemical stability, which solved the problem of chemical stability at high temperatures in the reported phosphor-in-silicone films. Moreover, the Trap depth in the phosphors and PiG films could be tailored from 1.2 to 1.6 eV, thanks to the bandgap engineering effect, and the emission color was simultaneously changed from green to yellow due to the variation of crystal field strength. Image information was recorded on the PiG films by using a 450 nm blue-light laser in a laser direct writing mode and the recorded information was retrieved under high-temperature thermal stimulation or photostimulation. The Y3Al5–xGaxO12:Ce3+,V3+ PiG films as presented in this work are very promising in the applications of multidimensional and rewritable optical information storage
N B Smirnov - One of the best experts on this subject based on the ideXlab platform.
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hydrogen plasma treatment of β ga2o3 changes in electrical properties and Deep Trap spectra
Applied Physics Letters, 2019Co-Authors: A Y Polyakov, Inhwan Lee, N B Smirnov, I V Shchemerov, E B Yakimov, A V Chernykh, A I Kochkova, A A Vasilev, F RenAbstract:The effects of hydrogen plasma treatment of β-Ga2O3 grown by halide vapor phase epitaxy and doped with Si are reported. Samples subjected to H plasma exposure at 330 °C developed a wide (∼2.5 μm-thick) region near the surface, depleted of electrons at room temperature. The thickness of the layer is in reasonable agreement with the estimated hydrogen penetration depth in β-Ga2O3 based on previous deuterium profiling experiments. Admittance spectroscopy and photoinduced current transient spectroscopy measurements place the Fermi level pinning position in the H treated film near Ec-1.05 eV. Annealing at 450 °C decreased the thickness of the depletion layer to 1.3 μm at room temperature and moved the Fermi level pinning position to Ec-0.8 eV. Further annealing at 550 °C almost restored the starting shallow donor concentration and the spectra of Deep Traps dominated by Ec-0.8 eV and Ec-1.05 eV observed before hydrogen treatment. It is suggested that hydrogen plasma exposure produces surface damage in the near-surface region and passivates or compensates shallow donors.The effects of hydrogen plasma treatment of β-Ga2O3 grown by halide vapor phase epitaxy and doped with Si are reported. Samples subjected to H plasma exposure at 330 °C developed a wide (∼2.5 μm-thick) region near the surface, depleted of electrons at room temperature. The thickness of the layer is in reasonable agreement with the estimated hydrogen penetration depth in β-Ga2O3 based on previous deuterium profiling experiments. Admittance spectroscopy and photoinduced current transient spectroscopy measurements place the Fermi level pinning position in the H treated film near Ec-1.05 eV. Annealing at 450 °C decreased the thickness of the depletion layer to 1.3 μm at room temperature and moved the Fermi level pinning position to Ec-0.8 eV. Further annealing at 550 °C almost restored the starting shallow donor concentration and the spectra of Deep Traps dominated by Ec-0.8 eV and Ec-1.05 eV observed before hydrogen treatment. It is suggested that hydrogen plasma exposure produces surface damage in the near-...
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Deep Trap analysis in green light emitting diodes problems and solutions
Journal of Applied Physics, 2019Co-Authors: A Y Polyakov, Inhwan Lee, N B Smirnov, I V Shchemerov, N M Shmidt, E I Shabunina, N A Talnishnih, L A Alexanyan, S A Tarelkin, S J PeartonAbstract:Some green light emitting diodes (LEDs) based on GaN/InGaN multiquantum-well (MQW) structures exhibit strong frequency and temperature dependence of capacitance and prominent changes in capacitance–voltage profiles with temperature that make it difficult to obtain reliable Deep level transient spectroscopy (DLTS) measurements. DLTS performed at low probing signal frequency and with constant capacitance between the measurements by controlling applied bias mitigates these issues. This allows measurement of Deep electron and hole Traps in specific quantum wells (QWs) in the MQW structure. The dominant electron and hole Traps detected have levels near Ec− (0.45–0.5) eV and Ev+ (0.6–0.63) eV. Their density increases significantly after aging for a long period (2120 h) at high driving current and elevated temperature. The reason for the observed anomalies in DLTS spectra of these green LEDs is the high density of states in the QWs with activation energies near 0.08, 0.12–0.14, and 0.3 eV, detected in admittance spectra, and, for the 0.08 eV and 0.3 eV, these states are likely related to defects.
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Deep Trap spectra of sn doped α ga 2 o 3 grown by halide vapor phase epitaxy on sapphire
APL Materials, 2019Co-Authors: A Y Polyakov, N B Smirnov, I V Shchemerov, E B Yakimov, A V Chernykh, V I Nikolaev, S I Stepanov, A I Pechnikov, K D ShcherbachevAbstract:Epitaxial layers of α-Ga2O3 with different Sn doping levels were grown by halide vapor phase epitaxy on sapphire. The films had shallow donor concentrations ranging from 1017 to 4.8 × 1019 cm−3. Deep level transient spectroscopy of the lowest doped samples revealed dominant A Traps with level Ec − 0.6 eV and B Traps near Ec − 1.1 eV. With increasing shallow donor concentration, the density of the A Traps increased, and new Traps C (Ec − 0.85 eV) and D (Ec − 0.23 eV) emerged. Photocapacitance spectra showed the presence of Deep Traps with optical ionization energy of ∼2 and 2.7 eV and prominent persistent photocapacitance at low temperature, surviving heating to temperatures above room temperature. The diffusion length of nonequilibrium charge carriers was 0.15 µm, and microcathodoluminescence spectra showed peaks in the range 339–540 nm, but no band-edge emission.Epitaxial layers of α-Ga2O3 with different Sn doping levels were grown by halide vapor phase epitaxy on sapphire. The films had shallow donor concentrations ranging from 1017 to 4.8 × 1019 cm−3. Deep level transient spectroscopy of the lowest doped samples revealed dominant A Traps with level Ec − 0.6 eV and B Traps near Ec − 1.1 eV. With increasing shallow donor concentration, the density of the A Traps increased, and new Traps C (Ec − 0.85 eV) and D (Ec − 0.23 eV) emerged. Photocapacitance spectra showed the presence of Deep Traps with optical ionization energy of ∼2 and 2.7 eV and prominent persistent photocapacitance at low temperature, surviving heating to temperatures above room temperature. The diffusion length of nonequilibrium charge carriers was 0.15 µm, and microcathodoluminescence spectra showed peaks in the range 339–540 nm, but no band-edge emission.
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Trap states in multication mesoscopic perovskite solar cells a Deep levels transient spectroscopy investigation
Applied Physics Letters, 2018Co-Authors: A Y Polyakov, N B Smirnov, I V Shchemerov, D Saranin, S I Didenko, Denis Kuznetsov, Antonio Agresti, Sara Pescetelli, Fabio Matteocci, A Di CarloAbstract:This work presents a study of Trap levels in a mesoscopic multication lead halide perovskite solar cell structure. The investigation is performed by combining capacitance measurements, admittance measurements, Deep Level Transient Spectroscopy (DLTS), and Optical DLTS. We found a donor level with an energy of 0.2 eV below the conduction band of perovskite. The donor density reaches a concentration of 1018 cm−3 in the accumulation region present at the interface between the perovskite and transporting layers. Other two Deep Trap levels are found with energies of 0.57 eV and 0.74 eV. The first level is related to a hole Trap while the second one to an electron Trap.
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defects responsible for lifetime degradation in electron irradiated n gan grown by hydride vapor phase epitaxy
Applied Physics Letters, 2017Co-Authors: Inhwan Lee, A Y Polyakov, N B Smirnov, I V Shchemerov, E B Yakimov, S A Tarelkin, S I Didenko, K I Tapero, R A ZinovyevAbstract:The effects of room temperature 6 MeV electron irradiation on the donor concentration, Deep Trap spectra, and diffusion lengths of nonequilibrium charge carriers were studied for undoped n-GaN grown by hydride vapor phase epitaxy. Changes in these parameters begin at a threshold electron fluence of 5 × 1015 cm−2. The diffusion lengths after this fluence decrease by a factor of 3, accompanied by a drastic increase in the density of Deep electron Traps with the level near Ec – 1 eV. There is a strong correlation between the changes in the density of these Traps and the diffusion length of irradiated n-GaN, indicating that these centers control the lifetime in radiation damaged n-GaN. This is in sharp contrast to the starting material, where the lifetimes are controlled by other Deep electron Traps at Ec – 0.56 eV. The concentration of the latter is not strongly affected by high energy electron irradiation.
E B Yakimov - One of the best experts on this subject based on the ideXlab platform.
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hydrogen plasma treatment of β ga2o3 changes in electrical properties and Deep Trap spectra
Applied Physics Letters, 2019Co-Authors: A Y Polyakov, Inhwan Lee, N B Smirnov, I V Shchemerov, E B Yakimov, A V Chernykh, A I Kochkova, A A Vasilev, F RenAbstract:The effects of hydrogen plasma treatment of β-Ga2O3 grown by halide vapor phase epitaxy and doped with Si are reported. Samples subjected to H plasma exposure at 330 °C developed a wide (∼2.5 μm-thick) region near the surface, depleted of electrons at room temperature. The thickness of the layer is in reasonable agreement with the estimated hydrogen penetration depth in β-Ga2O3 based on previous deuterium profiling experiments. Admittance spectroscopy and photoinduced current transient spectroscopy measurements place the Fermi level pinning position in the H treated film near Ec-1.05 eV. Annealing at 450 °C decreased the thickness of the depletion layer to 1.3 μm at room temperature and moved the Fermi level pinning position to Ec-0.8 eV. Further annealing at 550 °C almost restored the starting shallow donor concentration and the spectra of Deep Traps dominated by Ec-0.8 eV and Ec-1.05 eV observed before hydrogen treatment. It is suggested that hydrogen plasma exposure produces surface damage in the near-surface region and passivates or compensates shallow donors.The effects of hydrogen plasma treatment of β-Ga2O3 grown by halide vapor phase epitaxy and doped with Si are reported. Samples subjected to H plasma exposure at 330 °C developed a wide (∼2.5 μm-thick) region near the surface, depleted of electrons at room temperature. The thickness of the layer is in reasonable agreement with the estimated hydrogen penetration depth in β-Ga2O3 based on previous deuterium profiling experiments. Admittance spectroscopy and photoinduced current transient spectroscopy measurements place the Fermi level pinning position in the H treated film near Ec-1.05 eV. Annealing at 450 °C decreased the thickness of the depletion layer to 1.3 μm at room temperature and moved the Fermi level pinning position to Ec-0.8 eV. Further annealing at 550 °C almost restored the starting shallow donor concentration and the spectra of Deep Traps dominated by Ec-0.8 eV and Ec-1.05 eV observed before hydrogen treatment. It is suggested that hydrogen plasma exposure produces surface damage in the near-...
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Deep Trap spectra of sn doped α ga 2 o 3 grown by halide vapor phase epitaxy on sapphire
APL Materials, 2019Co-Authors: A Y Polyakov, N B Smirnov, I V Shchemerov, E B Yakimov, A V Chernykh, V I Nikolaev, S I Stepanov, A I Pechnikov, K D ShcherbachevAbstract:Epitaxial layers of α-Ga2O3 with different Sn doping levels were grown by halide vapor phase epitaxy on sapphire. The films had shallow donor concentrations ranging from 1017 to 4.8 × 1019 cm−3. Deep level transient spectroscopy of the lowest doped samples revealed dominant A Traps with level Ec − 0.6 eV and B Traps near Ec − 1.1 eV. With increasing shallow donor concentration, the density of the A Traps increased, and new Traps C (Ec − 0.85 eV) and D (Ec − 0.23 eV) emerged. Photocapacitance spectra showed the presence of Deep Traps with optical ionization energy of ∼2 and 2.7 eV and prominent persistent photocapacitance at low temperature, surviving heating to temperatures above room temperature. The diffusion length of nonequilibrium charge carriers was 0.15 µm, and microcathodoluminescence spectra showed peaks in the range 339–540 nm, but no band-edge emission.Epitaxial layers of α-Ga2O3 with different Sn doping levels were grown by halide vapor phase epitaxy on sapphire. The films had shallow donor concentrations ranging from 1017 to 4.8 × 1019 cm−3. Deep level transient spectroscopy of the lowest doped samples revealed dominant A Traps with level Ec − 0.6 eV and B Traps near Ec − 1.1 eV. With increasing shallow donor concentration, the density of the A Traps increased, and new Traps C (Ec − 0.85 eV) and D (Ec − 0.23 eV) emerged. Photocapacitance spectra showed the presence of Deep Traps with optical ionization energy of ∼2 and 2.7 eV and prominent persistent photocapacitance at low temperature, surviving heating to temperatures above room temperature. The diffusion length of nonequilibrium charge carriers was 0.15 µm, and microcathodoluminescence spectra showed peaks in the range 339–540 nm, but no band-edge emission.
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defects responsible for lifetime degradation in electron irradiated n gan grown by hydride vapor phase epitaxy
Applied Physics Letters, 2017Co-Authors: Inhwan Lee, A Y Polyakov, N B Smirnov, I V Shchemerov, E B Yakimov, S A Tarelkin, S I Didenko, K I Tapero, R A ZinovyevAbstract:The effects of room temperature 6 MeV electron irradiation on the donor concentration, Deep Trap spectra, and diffusion lengths of nonequilibrium charge carriers were studied for undoped n-GaN grown by hydride vapor phase epitaxy. Changes in these parameters begin at a threshold electron fluence of 5 × 1015 cm−2. The diffusion lengths after this fluence decrease by a factor of 3, accompanied by a drastic increase in the density of Deep electron Traps with the level near Ec – 1 eV. There is a strong correlation between the changes in the density of these Traps and the diffusion length of irradiated n-GaN, indicating that these centers control the lifetime in radiation damaged n-GaN. This is in sharp contrast to the starting material, where the lifetimes are controlled by other Deep electron Traps at Ec – 0.56 eV. The concentration of the latter is not strongly affected by high energy electron irradiation.
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electrical luminescent and Deep Trap properties of si doped n gan grown by pendeo epitaxy
Journal of Applied Physics, 2016Co-Authors: A Y Polyakov, Inhwan Lee, N B Smirnov, E B Yakimov, S J PeartonAbstract:Electrical and luminescent properties and Deep Trap spectra of Si doped GaN films grown by maskless epitaxial lateral overgrowth (MELO) are reported. The dislocation density in the wing region of the structure was 106 cm−2, while in the seed region it was 108 cm−2. The major electron Traps present had activation energy of 0.56 eV and concentrations in the high 1015 cm−3 range. A comparison of diffusion length values and 0.56 eV Trap concentration in MELO GaN and epitaxial lateral overgrowth (ELOG) GaN showed a good correlation, suggesting these Traps could be effective in carrier recombination. The doped MELO films were more uniform in their electrical properties than either ELOG films or undoped MELO films. We also discuss the differences in Deep Trap spectra and luminescence spectra of low-dislocation-density MELO, ELOG, and bulk n-GaN samples grown by hydride vapor phase epitaxy. It is suggested that the observed differences could be caused by the differences in oxygen and carbon contamination levels.
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effects of laterally overgrown n gan thickness on defect and Deep level concentrations
Journal of Vacuum Science & Technology B, 2008Co-Authors: A Y Polyakov, N B Smirnov, E B Yakimov, A V Govorkov, A V Markov, P S Vergeles, S J PeartonAbstract:The effects of the layer thickness and of Si doping on the dislocation type and density, electron concentration, and Deep Trap spectra were studied for epitaxially laterally overgrown (ELOG) GaN films with the ELOG region thickness varying from 6to12μm. Electron beam induced current imaging shows that for the thickest layers, the major part of the threading dislocations are filtered out while for thinner films they bend, but do not go out of play. The concentration of residual donors and major electron Traps is found to decrease with increasing the film thickness. Si doping suppresses the concentration of the main electron Trap with activation energy of 0.6eV and enhances the concentration of the main hole Trap at Ev+0.85eV.
Yixi Zhuang - One of the best experts on this subject based on the ideXlab platform.
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tailoring Trap depth and emission wavelength in y3al5 xgaxo12 ce3 v3 phosphor in glass films for optical information storage
ACS Applied Materials & Interfaces, 2018Co-Authors: Yixi Zhuang, Peng Zheng, Tianliang Zhou, Jumpei Ueda, Setsuhisa Tanabe, Le Wang, Rongjun XieAbstract:Deep-Trap persistent luminescent materials, due to their exceptional ability of energy storage and controllable photon release under external stimulation, have attracted considerable attention in the field of optical information storage. Currently, the lack of suitable materials is still the bottleneck that restrains their practical applications. Herein, we successfully synthesized a series of Deep-Trap persistent luminescent materials Y3Al5–xGaxO12:Ce3+,V3+ (x = 0–3) with a garnet structure and developed novel phosphor-in-glass (PiG) films containing these phosphors. The synthesized PiG films exhibited sufficiently Deep Traps, narrow Trap depth distributions, high Trap density, high quantum efficiency, and excellent chemical stability, which solved the problem of chemical stability at high temperatures in the reported phosphor-in-silicone films. Moreover, the Trap depth in the phosphors and PiG films could be tailored from 1.2 to 1.6 eV, thanks to the bandgap engineering effect, and the emission color wa...
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Trap depth engineering of srsi2o2n2 ln2 ln3 ln2 yb eu ln3 dy ho er persistent luminescence materials for information storage applications
ACS Applied Materials & Interfaces, 2018Co-Authors: Yixi Zhuang, Tianliang Zhou, Le Wang, Wenwei Chen, Takashi Takeda, Naoto Hirosaki, Rongjun XieAbstract:Deep-Trap persistent luminescence materials exhibit unique properties of energy storage and controllable photon release under additional stimulation, allowing for both wavelength and intensity multiplexing to realize high-capacity storage in the next-generation information storage system. However, the lack of suitable persistent luminescence materials with Deep Traps is the bottleneck of such storage technologies. In this study, we successfully developed a series of novel Deep-Trap persistent luminescence materials in the Ln2+/Ln3+-doped SrSi2O2N2 system (Ln2+ = Yb, Eu; Ln3+ = Dy, Ho, Er) by applying the strategy of Trap depth engineering. Interestingly, the Trap depth can be tailored by selecting different codopants, and it monotonically increases from 0.90 to 1.18 eV in the order of Er, Ho, and Dy. This is well explained by the energy levels indicated in the host-referred binding energy scheme. The orange-red-emitting SrSi2O2N2:Yb,Dy and green-emitting SrSi2O2N2:Eu,Dy phosphors are demonstrated to be go...
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Tailoring Trap Depth and Emission Wavelength in Y3Al5–xGaxO12:Ce3+,V3+ Phosphor-in-Glass Films for Optical Information Storage
2018Co-Authors: Yixi Zhuang, Peng Zheng, Tianliang Zhou, Jumpei Ueda, Setsuhisa Tanabe, Le Wang, Rongjun XieAbstract:Deep-Trap persistent luminescent materials, due to their exceptional ability of energy storage and controllable photon release under external stimulation, have attracted considerable attention in the field of optical information storage. Currently, the lack of suitable materials is still the bottleneck that restrains their practical applications. Herein, we successfully synthesized a series of Deep-Trap persistent luminescent materials Y3Al5–xGaxO12:Ce3+,V3+ (x = 0–3) with a garnet structure and developed novel phosphor-in-glass (PiG) films containing these phosphors. The synthesized PiG films exhibited sufficiently Deep Traps, narrow Trap depth distributions, high Trap density, high quantum efficiency, and excellent chemical stability, which solved the problem of chemical stability at high temperatures in the reported phosphor-in-silicone films. Moreover, the Trap depth in the phosphors and PiG films could be tailored from 1.2 to 1.6 eV, thanks to the bandgap engineering effect, and the emission color was simultaneously changed from green to yellow due to the variation of crystal field strength. Image information was recorded on the PiG films by using a 450 nm blue-light laser in a laser direct writing mode and the recorded information was retrieved under high-temperature thermal stimulation or photostimulation. The Y3Al5–xGaxO12:Ce3+,V3+ PiG films as presented in this work are very promising in the applications of multidimensional and rewritable optical information storage
