The Experts below are selected from a list of 10152 Experts worldwide ranked by ideXlab platform
S V Poltavtsev - One of the best experts on this subject based on the ideXlab platform.
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steplike spectral distribution of photoElectrons at the percolation threshold in heavily p doped gaas
Physical Review B, 2020Co-Authors: S V Poltavtsev, R I Dzhioev, V L Korenev, I A Akimov, D Kudlacik, D R Yakovlev, M BayerAbstract:We study the origin of the step-like shoulder on the high energy side of the low temperature photoluminescence spectrum of heavily $p$-doped GaAs. We show experimentally that it is controlled by the Fermi-Dirac distribution of the holes and by the energy distribution of the photoexcited Electrons showing a sharp step-like dependence. This step is attributed to the percolation threshold in the conduction band separating localized from Delocalized Electron states. A comprehensive set of optical techniques based on spin orientation of Electrons, namely the Hanle effect, time- and polarization-resolved photoluminescence, as well as transient pump-probe Faraday rotation are used for these studies. We identify two different Electron ensembles with substantially different spin lifetimes of 20 and 280~ps, limited by the lifetime of the Electrons. Their spin relaxation times are longer than 2~ns. The relative contribution of short- and long-lived photoexcited Electrons to the emission spectrum changes abruptly at the high-energy photoluminescence step-like tail. For energies above the percolation threshold the Electron states are empty due to fast energy relaxation, while for lower energies the relaxation is suppressed and the majority of photoElectrons populate these states.
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steplike spectral distribution of photoElectrons at the percolation threshold in heavily p doped gaas
Physical Review B, 2020Co-Authors: S V Poltavtsev, R I Dzhioev, V L Korenev, I A Akimov, D Kudlacik, D R Yakovlev, M BayerAbstract:The origin of the steplike shoulder on the high-energy side of the low-temperature photoluminescence spectrum of heavily $p$-doped GaAs is studied experimentally. It is shown that it is controlled by both the Fermi-Dirac distribution of the holes and the energy distribution of the photoexcited Electrons exhibiting a sharp steplike dependence. The latter results from abrupt changes in the energy relaxation rate at the percolation threshold separating localized from Delocalized Electron states. A comprehensive set of optical techniques based on spin orientation of Electrons, namely, the Hanle effect, time- and polarization-resolved photoluminescence, as well as transient pump-probe Faraday rotation, are used for these studies. Two different Electron ensembles with substantially different lifetimes of 20 and 280 ps are identified. Their spin relaxation times are longer than 2 ns, so that the spin lifetime is limited by the Electron lifetime. The relative contribution of short- and long-lived photoexcited Electrons to the emission spectrum changes abruptly at the step in the high-energy photoluminescence tail. For energies above the percolation threshold, the Electron states are empty due to fast energy relaxation, while for lower energies the relaxation is suppressed and the majority of photoElectrons populates the states located there.
M Bayer - One of the best experts on this subject based on the ideXlab platform.
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steplike spectral distribution of photoElectrons at the percolation threshold in heavily p doped gaas
Physical Review B, 2020Co-Authors: S V Poltavtsev, R I Dzhioev, V L Korenev, I A Akimov, D Kudlacik, D R Yakovlev, M BayerAbstract:We study the origin of the step-like shoulder on the high energy side of the low temperature photoluminescence spectrum of heavily $p$-doped GaAs. We show experimentally that it is controlled by the Fermi-Dirac distribution of the holes and by the energy distribution of the photoexcited Electrons showing a sharp step-like dependence. This step is attributed to the percolation threshold in the conduction band separating localized from Delocalized Electron states. A comprehensive set of optical techniques based on spin orientation of Electrons, namely the Hanle effect, time- and polarization-resolved photoluminescence, as well as transient pump-probe Faraday rotation are used for these studies. We identify two different Electron ensembles with substantially different spin lifetimes of 20 and 280~ps, limited by the lifetime of the Electrons. Their spin relaxation times are longer than 2~ns. The relative contribution of short- and long-lived photoexcited Electrons to the emission spectrum changes abruptly at the high-energy photoluminescence step-like tail. For energies above the percolation threshold the Electron states are empty due to fast energy relaxation, while for lower energies the relaxation is suppressed and the majority of photoElectrons populate these states.
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steplike spectral distribution of photoElectrons at the percolation threshold in heavily p doped gaas
Physical Review B, 2020Co-Authors: S V Poltavtsev, R I Dzhioev, V L Korenev, I A Akimov, D Kudlacik, D R Yakovlev, M BayerAbstract:The origin of the steplike shoulder on the high-energy side of the low-temperature photoluminescence spectrum of heavily $p$-doped GaAs is studied experimentally. It is shown that it is controlled by both the Fermi-Dirac distribution of the holes and the energy distribution of the photoexcited Electrons exhibiting a sharp steplike dependence. The latter results from abrupt changes in the energy relaxation rate at the percolation threshold separating localized from Delocalized Electron states. A comprehensive set of optical techniques based on spin orientation of Electrons, namely, the Hanle effect, time- and polarization-resolved photoluminescence, as well as transient pump-probe Faraday rotation, are used for these studies. Two different Electron ensembles with substantially different lifetimes of 20 and 280 ps are identified. Their spin relaxation times are longer than 2 ns, so that the spin lifetime is limited by the Electron lifetime. The relative contribution of short- and long-lived photoexcited Electrons to the emission spectrum changes abruptly at the step in the high-energy photoluminescence tail. For energies above the percolation threshold, the Electron states are empty due to fast energy relaxation, while for lower energies the relaxation is suppressed and the majority of photoElectrons populates the states located there.
D R Yakovlev - One of the best experts on this subject based on the ideXlab platform.
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steplike spectral distribution of photoElectrons at the percolation threshold in heavily p doped gaas
Physical Review B, 2020Co-Authors: S V Poltavtsev, R I Dzhioev, V L Korenev, I A Akimov, D Kudlacik, D R Yakovlev, M BayerAbstract:We study the origin of the step-like shoulder on the high energy side of the low temperature photoluminescence spectrum of heavily $p$-doped GaAs. We show experimentally that it is controlled by the Fermi-Dirac distribution of the holes and by the energy distribution of the photoexcited Electrons showing a sharp step-like dependence. This step is attributed to the percolation threshold in the conduction band separating localized from Delocalized Electron states. A comprehensive set of optical techniques based on spin orientation of Electrons, namely the Hanle effect, time- and polarization-resolved photoluminescence, as well as transient pump-probe Faraday rotation are used for these studies. We identify two different Electron ensembles with substantially different spin lifetimes of 20 and 280~ps, limited by the lifetime of the Electrons. Their spin relaxation times are longer than 2~ns. The relative contribution of short- and long-lived photoexcited Electrons to the emission spectrum changes abruptly at the high-energy photoluminescence step-like tail. For energies above the percolation threshold the Electron states are empty due to fast energy relaxation, while for lower energies the relaxation is suppressed and the majority of photoElectrons populate these states.
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steplike spectral distribution of photoElectrons at the percolation threshold in heavily p doped gaas
Physical Review B, 2020Co-Authors: S V Poltavtsev, R I Dzhioev, V L Korenev, I A Akimov, D Kudlacik, D R Yakovlev, M BayerAbstract:The origin of the steplike shoulder on the high-energy side of the low-temperature photoluminescence spectrum of heavily $p$-doped GaAs is studied experimentally. It is shown that it is controlled by both the Fermi-Dirac distribution of the holes and the energy distribution of the photoexcited Electrons exhibiting a sharp steplike dependence. The latter results from abrupt changes in the energy relaxation rate at the percolation threshold separating localized from Delocalized Electron states. A comprehensive set of optical techniques based on spin orientation of Electrons, namely, the Hanle effect, time- and polarization-resolved photoluminescence, as well as transient pump-probe Faraday rotation, are used for these studies. Two different Electron ensembles with substantially different lifetimes of 20 and 280 ps are identified. Their spin relaxation times are longer than 2 ns, so that the spin lifetime is limited by the Electron lifetime. The relative contribution of short- and long-lived photoexcited Electrons to the emission spectrum changes abruptly at the step in the high-energy photoluminescence tail. For energies above the percolation threshold, the Electron states are empty due to fast energy relaxation, while for lower energies the relaxation is suppressed and the majority of photoElectrons populates the states located there.
I A Akimov - One of the best experts on this subject based on the ideXlab platform.
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steplike spectral distribution of photoElectrons at the percolation threshold in heavily p doped gaas
Physical Review B, 2020Co-Authors: S V Poltavtsev, R I Dzhioev, V L Korenev, I A Akimov, D Kudlacik, D R Yakovlev, M BayerAbstract:We study the origin of the step-like shoulder on the high energy side of the low temperature photoluminescence spectrum of heavily $p$-doped GaAs. We show experimentally that it is controlled by the Fermi-Dirac distribution of the holes and by the energy distribution of the photoexcited Electrons showing a sharp step-like dependence. This step is attributed to the percolation threshold in the conduction band separating localized from Delocalized Electron states. A comprehensive set of optical techniques based on spin orientation of Electrons, namely the Hanle effect, time- and polarization-resolved photoluminescence, as well as transient pump-probe Faraday rotation are used for these studies. We identify two different Electron ensembles with substantially different spin lifetimes of 20 and 280~ps, limited by the lifetime of the Electrons. Their spin relaxation times are longer than 2~ns. The relative contribution of short- and long-lived photoexcited Electrons to the emission spectrum changes abruptly at the high-energy photoluminescence step-like tail. For energies above the percolation threshold the Electron states are empty due to fast energy relaxation, while for lower energies the relaxation is suppressed and the majority of photoElectrons populate these states.
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steplike spectral distribution of photoElectrons at the percolation threshold in heavily p doped gaas
Physical Review B, 2020Co-Authors: S V Poltavtsev, R I Dzhioev, V L Korenev, I A Akimov, D Kudlacik, D R Yakovlev, M BayerAbstract:The origin of the steplike shoulder on the high-energy side of the low-temperature photoluminescence spectrum of heavily $p$-doped GaAs is studied experimentally. It is shown that it is controlled by both the Fermi-Dirac distribution of the holes and the energy distribution of the photoexcited Electrons exhibiting a sharp steplike dependence. The latter results from abrupt changes in the energy relaxation rate at the percolation threshold separating localized from Delocalized Electron states. A comprehensive set of optical techniques based on spin orientation of Electrons, namely, the Hanle effect, time- and polarization-resolved photoluminescence, as well as transient pump-probe Faraday rotation, are used for these studies. Two different Electron ensembles with substantially different lifetimes of 20 and 280 ps are identified. Their spin relaxation times are longer than 2 ns, so that the spin lifetime is limited by the Electron lifetime. The relative contribution of short- and long-lived photoexcited Electrons to the emission spectrum changes abruptly at the step in the high-energy photoluminescence tail. For energies above the percolation threshold, the Electron states are empty due to fast energy relaxation, while for lower energies the relaxation is suppressed and the majority of photoElectrons populates the states located there.
Natia L Frank - One of the best experts on this subject based on the ideXlab platform.
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ferromagnetic spin Delocalized Electron donors for multifunctional materials π conjugated benzotriazinyl radicals
Chemical Communications, 2011Co-Authors: Jordan Cramen, Robert Mcdonald, Natia L FrankAbstract:We have developed new synthetic methodology for benzotriazinyl radicals that exhibit spin delocalization, low oxidation potentials, and ferromagnetic interactions in the solid state via π–π interactions, making them promising candidates for multifunctional magnetic materials.
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synthesis of neutral spin Delocalized Electron acceptors for multifunctional materials
Organic Letters, 2007Co-Authors: Brynn M Dooley, Steven E Bowles, Tim Storr, Natia L FrankAbstract:A new synthetic route to stable spin-Delocalized radicals, annelated nitronyl nitroxides, has been developed on the basis of the condensation of benzofuroxan with aryl nitrones. The Electronic structure of the resulting radicals was investigated through absorption spectroscopy, EPR, electrochemistry, and computation (DFT-UB3LYP). The annelated radicals exhibit Electronic transitions in the near IR (850-900 nm) and are excellent Electron acceptors (E(red) approximately 0.0 vs SCE) ideal for the development of multifunctional magnetic materials.