The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Todd D Krauss - One of the best experts on this subject based on the ideXlab platform.
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quantized bimolecular Auger recombination of excitons in single walled carbon nanotubes
Physical Review Letters, 2006Co-Authors: Libai Huang, Todd D KraussAbstract:Auger-like exciton-exciton annihilation in isolated single-walled carbon nanotubes (SWNTs) has been studied by femtosecond transient absorption spectroscopy. We observe a quantization of the Auger recombination Process and extract dynamics for 2 and 3 electron-hole pair excited states. We further demonstrate that Auger recombination in SWNTs is a two-particle Process involving strongly bound excitons and not a three-particle Auger Process involving unbound electrons and holes. We thus provide explicit experimental evidence for one-dimensional discrete excitons in SWNTs.
Marc Ziegler - One of the best experts on this subject based on the ideXlab platform.
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Biexciton, single carrier, and trion generation dynamics in single-walled carbon nanotubes
Physical Review B: Condensed Matter and Materials Physics, 2013Co-Authors: Bertrand Yuma, Stéphane Berciaud, Jean Besbas, Jonah Shaver, Silvia M. Santos, Saunab Gosh, R. Bruce Weisman, Laurent Cognet, Mathieu Gallart, Marc ZieglerAbstract:We present a study of free carrier photo-generation and multi-carrier bound states, such as biexcitons and trions (ionized excitons), in semiconducting single-walled carbon nanotubes. Pump-and-probe measurements performed with fs pulses reveal the effects of strong Coulomb interactions between carriers on their dynamics. Biexciton formation by optical transition from exciton population results in an induced absorption line (binding energy 130 meV). Exciton-exciton annihilation Process is shown to evolve at high densities towards an Auger Process that can expel carriers from nanotubes. The remaining carriers give rise to an induced absorption due to trion formation (binding energy 190 meV). These features show the dynamics of exciton and free carriers populations.
Margit Zacharias - One of the best experts on this subject based on the ideXlab platform.
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enhanced defect luminescence due to fast Auger Process in cuprous iodide structures produced by solvent anti solvent crystallization
Journal of Luminescence, 2020Co-Authors: Deniz Yazicioglu, Yun Cai, Sebastian Gutsch, Yang Yang, J Lopezvidrier, Margit ZachariasAbstract:Abstract Photoluminescence spectra of self-assembled cuprous iodide structures produced by solvent-antisolvent crystallization were investigated over eight orders of magnitude of excitation power density. Through an analysis of the effects of different annealing conditions on the emission spectra two defects-related emissions, associated to copper and iodine vacancies, and a free exciton recombination peak were identified. At higher power densities, an enhanced increase in the broad defects-related emission band accompanied by a decrease in other contributions was observed. A fast, non-radiative Auger Process is proposed as the main mechanism allowing high energy electrons to be trapped at deep level defects associated to the broad defects-related emission band while simultaneously reducing the amount of free charge carriers, which results in the observed behavior. With a rate-equation model developed for the proposed mechanism a close fit between simulated and experimental data was achieved.
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Enhanced defect luminescence due to fast Auger Process in cuprous iodide structures produced by solvent/anti-solvent crystallization
Journal of Luminescence, 2020Co-Authors: Deniz Yazicioglu, Yun Cai, Sebastian Gutsch, J. López-vidrier, Yang Yang, Margit ZachariasAbstract:Abstract Photoluminescence spectra of self-assembled cuprous iodide structures produced by solvent-antisolvent crystallization were investigated over eight orders of magnitude of excitation power density. Through an analysis of the effects of different annealing conditions on the emission spectra two defects-related emissions, associated to copper and iodine vacancies, and a free exciton recombination peak were identified. At higher power densities, an enhanced increase in the broad defects-related emission band accompanied by a decrease in other contributions was observed. A fast, non-radiative Auger Process is proposed as the main mechanism allowing high energy electrons to be trapped at deep level defects associated to the broad defects-related emission band while simultaneously reducing the amount of free charge carriers, which results in the observed behavior. With a rate-equation model developed for the proposed mechanism a close fit between simulated and experimental data was achieved.
Mahesh Kumar - One of the best experts on this subject based on the ideXlab platform.
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enhanced carrier density in a mos 2 si heterojunction based photodetector by inverse Auger Process
IEEE Transactions on Electron Devices, 2018Co-Authors: Neeraj Goel, Rahul Kumar, Mirabbos Hojamberdiev, Mahesh KumarAbstract:When exploring the charge transport in the MoS2/Si heterojunction, it is imperative to understand the contribution of different carrier interactions and scattering mechanisms in the conduction Process. Here, we have demonstrated an ultrasensitive photodetector based on MoS2/Si (for both p-type and n-type Si) van der Walls (vdW) heterojunction, which provides a high photoresponsivity of greater than 103 A/W along with a large detectivity of ≈ 1012 Jones (Jones = $\text{cm} \cdot \text{Hz}^{ {1/2}} \cdot \text{W}^{-1}$ ). This high photoresponsivity is attributed to the high absorption rate of incident photons and large current carrying capacity of a few layer MoS2. The tuning of barrier height at the MoS2/n-Si interface with photoexcitation of different wavelengths was interpreted by using Bardeen’s model. The increase in carrier density due to the photon energy results in a reduction of barrier height at the heterojunction. Because of increase in carrier density with wavelength, it was observed that the inverse Auger Process prevails at higher wavelength for the relaxation of photoinduced charge carriers at the MoS2/Si interface over other scattering mechanisms. Our obtained results unveil the great potential of the MoS2/Si vdW heterojunction that may pave the way for new generation photodetectors.
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Enhanced Carrier Density in a MoS 2 /Si Heterojunction-Based Photodetector by Inverse Auger Process
IEEE Transactions on Electron Devices, 2018Co-Authors: Neeraj Goel, Rahul Kumar, Mirabbos Hojamberdiev, Mahesh KumarAbstract:When exploring the charge transport in the MoS2/Si heterojunction, it is imperative to understand the contribution of different carrier interactions and scattering mechanisms in the conduction Process. Here, we have demonstrated an ultrasensitive photodetector based on MoS2/Si (for both p-type and n-type Si) van der Walls (vdW) heterojunction, which provides a high photoresponsivity of greater than 103 A/W along with a large detectivity of ≈ 1012 Jones (Jones = $\text{cm} \cdot \text{Hz}^{ {1/2}} \cdot \text{W}^{-1}$ ). This high photoresponsivity is attributed to the high absorption rate of incident photons and large current carrying capacity of a few layer MoS2. The tuning of barrier height at the MoS2/n-Si interface with photoexcitation of different wavelengths was interpreted by using Bardeen’s model. The increase in carrier density due to the photon energy results in a reduction of barrier height at the heterojunction. Because of increase in carrier density with wavelength, it was observed that the inverse Auger Process prevails at higher wavelength for the relaxation of photoinduced charge carriers at the MoS2/Si interface over other scattering mechanisms. Our obtained results unveil the great potential of the MoS2/Si vdW heterojunction that may pave the way for new generation photodetectors.
S Ricz - One of the best experts on this subject based on the ideXlab platform.
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near k edge double and triple detachment of the f negative ion observation of direct two electron ejection by a single photon
Physical Review Letters, 2018Co-Authors: A Muller, A Borovik, Sadia Bari, T Buhr, K Holste, M Martins, A Perrysasmannshausen, R A Phaneuf, S Reinwardt, S RiczAbstract:Double and triple detachment of the ${\mathrm{F}}^{\ensuremath{-}}(1{s}^{2}2{s}^{2}2{p}^{6})$ negative ion by a single photon have been investigated in the photon energy range 660 to 1000 eV. The experimental data provide unambiguous evidence for the dominant role of direct photodouble detachment with a subsequent single-Auger Process in the reaction channel leading to ${\mathrm{F}}^{2+}$ product ions. Absolute cross sections were determined for the direct removal of a $(1s+2p)$ pair of electrons from ${\mathrm{F}}^{\ensuremath{-}}$ by the absorption of a single photon.
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observation of a four electron Auger Process in near k edge photoionization of singly charged carbon ions
Physical Review Letters, 2015Co-Authors: A Muller, A Borovik, T Buhr, K Holste, M Martins, S Ricz, J Hellhund, A L D Kilcoyne, S Klumpp, J. ViefhausAbstract:: Single, double, and triple ionization of C(1+) ions by single photons is investigated in the energy range of 286-326 eV, i.e., in the range from the lowest-energy K-vacancy resonances to well beyond the K-shell ionization threshold. Clear signatures of C(1+)(1s2s(2)2p(2) (2)D,(2)P) resonances are found in the triple-ionization channel. The only possible mechanism producing C(4+)(1s(2)) via these resonances is direct triple-Auger decay, i.e., a four-electron Process with simultaneous emission of three electrons.
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observation of a four electron Auger Process in near k edge photoionization of singly charged carbon ions
Physical Review Letters, 2015Co-Authors: A Muller, A Borovik, T Buhr, K Holste, M Martins, J Hellhund, A L D Kilcoyne, S Klumpp, S RiczAbstract:Using a new photon-ion merged-beam setup at PETRA III, DESY, resonant Auger decay in which three electrons are emitted simultaneously is observed in carbon ions.