The Experts below are selected from a list of 16290 Experts worldwide ranked by ideXlab platform
Eli Kapon - One of the best experts on this subject based on the ideXlab platform.
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high internal Quantum efficiency narrow linewidth ingaas gaas algaas Quantum Wire light emitting diodes
Applied Physics Letters, 2002Co-Authors: H Weman, L Sirigu, Klaus Leifer, Amit Rudra, K F Karlsson, Eli KaponAbstract:High internal Quantum efficiency (∼60%), narrow linewidth (as narrow as 14 meV) exciton emission at room temperature has been obtained using strained InGaAs V-groove Quantum Wire (QWR) light-emitting diodes (LEDs). The high efficiency is achieved with the aid of selective carrier injection through self-ordered AlGaAs vertical Quantum wells (VQWs), where the VQWs are separated from the InGaAs QWRs by thin GaAs spacer layers in order to reduce nonradiative recombination and inhomogeneous alloy broadening. Evidence for excitonic recombination in these LEDs up to RT is provided by measurements of the emission energy shifts at high magnetic fields.
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efficient narrow linewidth emission from ingaas algaas v groove Quantum Wire light emitting diodes
International Conference on Indium Phosphide and Related Materials, 2002Co-Authors: H Weman, L Sirigu, Klaus Leifer, K F Karlsson, Alok Rudra, Eli KaponAbstract:We have succeeded to achieve highly efficient, narrow linewidth electroluminescence (EL) at room temperature from strained InGaAs Quantum Wire (QWR) light-emitting diodes (LEDs). The internal Quantum efficiency is estimated to be as high as 60% for a single layer, 500-nm-pitch V-groove In/sub 0.15/Ga/sub 0.85/As QWR array LED, emitting at 1.29 eV (/spl lambda/ = 960 nm) with a linewidth as narrow as 14 meV. The high efficiency is achieved with the aid of selective carrier injection directly into the QWRs through self-ordered AlGaAs vertical Quantum wells (VQWs), where the VQWs were separated from the InGaAs QWRs by thin GaAs spacer layers in order to reduce nonradiative recombination and inhomogeneous alloy broadening.
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efficient narrow linewidth excitonic emission at room temperature from gaas algaas v groove Quantum Wire light emitting diodes
Applied Physics Letters, 2001Co-Authors: H Weman, Amit Rudra, M A Dupertuis, E Martinet, Eli KaponAbstract:We report on efficient, narrow linewidth exciton recombination in GaAs/AlGaAs V-groove Quantum Wire light-emitting diodes at room temperature. The high efficiency is due to a selective carrier injection mechanism resulting in an estimated internal Quantum efficiency of ∼20% with an electroluminescence (EL) linewidth as narrow as 15 meV. The thermal broadening contribution to the linewidth is 6 meV due to exciton scattering with optical phonons. An analysis of the EL peak shift in a magnetic field points out the typical superlinear behavior of the excitonic binding energy for a Quantum Wire.
Felix Von Oppen - One of the best experts on this subject based on the ideXlab platform.
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enhanced zero bias majorana peak in the differential tunneling conductance of disordered multisubband Quantum Wire superconductor junctions
Physical Review Letters, 2012Co-Authors: Falko Pientka, Graham Kells, Alessandro Romito, Piet W Brouwer, Felix Von OppenAbstract:A recent experiment Mourik et al. [Science 336, 1003 (2012)] on InSb Quantum Wires provides possible evidence for the realization of a topological superconducting phase and the formation of Majorana bound states. Motivated by this experiment, we consider the signature of Majorana bound states in the differential tunneling conductance of multisubband Wires. We show that the weight of the Majoranainduced zero-bias peak is strongly enhanced by mixing of subbands, when disorder is added to the end of the Quantum Wire. We also consider how the topological phase transition is reflected in the gap structure of
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enhanced zero bias majorana peak in the differential tunneling conductance of disordered multisubband Quantum Wire superconductor junctions
Physical Review Letters, 2012Co-Authors: Falko Pientka, Graham Kells, Alessandro Romito, Piet W Brouwer, Felix Von OppenAbstract:A recent experiment Mourik et al. [Science 336, 1003 (2012)] on InSb Quantum Wires provides possible evidence for the realization of a topological superconducting phase and the formation of Majorana bound states. Motivated by this experiment, we consider the signature of Majorana bound states in the differential tunneling conductance of multisubband Wires. We show that the weight of the Majorana-induced zero-bias peak is strongly enhanced by mixing of subbands, when disorder is added to the end of the Quantum Wire. We also consider how the topological phase transition is reflected in the gap structure of the current-voltage characteristic.
K W West - One of the best experts on this subject based on the ideXlab platform.
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lasing from a single Quantum Wire
Applied Physics Letters, 2002Co-Authors: Yuhei Hayamizu, Hidefumi Akiyama, Masahiro Yoshita, Shinichi Watanabe, L N Pfeiffer, K W WestAbstract:A laser with an active volume consisting of only a single-Quantum Wire in the one-dimensional (1D) ground state is demonstrated. The single Wire is formed Quantum mechanically at the T-shaped intersection of a 14 nm Al0.07Ga0.93As Quantum well and a 6 nm GaAs Quantum well, and is embedded in a 1D single-mode optical waveguide. We observe single-mode lasing from the Quantum-Wire ground state by optical pumping. The laser operates from 5 to 60 K, and has a low threshold pumping power of 5 mW at 5 K.
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lasing from a single Quantum Wire
arXiv: Materials Science, 2002Co-Authors: Yuhei Hayamizu, Hidefumi Akiyama, Masahiro Yoshita, Shinichi Watanabe, L N Pfeiffer, K W WestAbstract:A laser with an active volume consisting of only a single Quantum Wire in the 1-dimensional (1-D) ground state is demonstrated. The single Wire is formed Quantum-mechanically at the T-intersection of a 14 nm Al_{0.07}Ga_{0.93}As Quantum well and a 6 nm GaAs Quantum well, and is embedded in a 1-D single-mode optical waveguide. We observe single-mode lasing from the Quantum Wire ground state by optical pumping. The laser operates from 5 to 60 K, and has a low threshold pumping power of 5 mW at 5 K.
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four terminal resistance of a ballistic Quantum Wire
Nature, 2001Co-Authors: R De Picciotto, L N Pfeiffer, H L Stormer, K W Baldwin, K W WestAbstract:The electrical resistance of a conductor is intimately related to the relaxation of the momentum of charge carriers. In a simple model, the accelerating force exerted on electrons by an applied electric field is balanced by a frictional force arising from their frequent collisions with obstacles such as impurities, grain boundaries or other deviations from a perfect crystalline order1. Thus, in the absence of any scattering, the electrical resistance should vanish altogether. Here, we observe such vanishing four-terminal resistance in a single-mode ballistic Quantum Wire. This result contrasts the value of the standard two-probe resistance measurements of h/2e2≈ 13 kΩ. The measurements are conducted in the highly controlled geometry afforded by epitaxial growth onto the cleaved edge of a high-quality GaAs/AlGaAs heterostructure. Two weakly invasive voltage probes are attached to the central section of a ballistic Quantum Wire to measure the inherent resistance of this clean one-dimensional conductor.
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experimental evidence for resonant tunneling in a luttinger liquid
Physical Review Letters, 2000Co-Authors: O M Auslaender, L N Pfeiffer, R De Picciotto, K W Baldwin, Amir Yacoby, K W WestAbstract:We have measured the low-temperature conductance of a one-dimensional island embedded in a single mode Quantum Wire. The Quantum Wire is fabricated using the cleaved edge overgrowth technique and the tunneling is through a single state of the island. Our results show that while the resonance line shape fits the derivative of the Fermi function the intrinsic linewidth decreases in a power law fashion as the temperature is reduced. This behavior agrees quantitatively with Furusaki's model for resonant tunneling in a Luttinger liquid.
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metamorphosis of a Quantum Wire into Quantum dots
Nature, 1997Co-Authors: J Hasen, L N Pfeiffer, K W West, Aron Pinczuk, B S DennisAbstract:Bound states of electron–hole pairs (excitons) in semiconductors possess desirable properties — such as an enhanced oscillator strength for radiative recombination — that hold promise for the next generation of optical devices. However, at typical device operating conditions (room temperature and moderate charge densities), excitons dissociate to form an electron–hole plasma. Dissociation may be prevented by confining excitons to lower dimensions, where their binding energy is expected to increase significantly1. But such confinement may in turn influence the dynamical properties of the excitons. Here we report spatially resolved photoluminescence images of excitons confined to an isolated gallium arsenide Quantum Wire. As the temperature of the structure is lowered, we observe a striking transition from broad and fairly continuous photoluminescence to an intense set of emission peaks which are both energetically sharp and spatially localized. Such behaviour indicates that, at sufficiently low temperatures, the Quantum Wire acts like a sparse set of Quantum dots. Furthermore, at the site of an isolated Quantum dot, we observe an unusual decrease in the relaxation rate of excitons, such that they radiate (via recombination) from higher energy states before relaxing to their ground state. We argue that this is the manifestation of an exciton relaxation ‘bottleneck’, the existence of which could pose problems for the development of optical devices based on Quantum dots.
L N Pfeiffer - One of the best experts on this subject based on the ideXlab platform.
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observation of a one dimensional spin orbit gap in a Quantum Wire
Nature Physics, 2010Co-Authors: L N Pfeiffer, K W Baldwin, C H L Quay, Taylor L Hughes, Joseph A SulpizioAbstract:The ability to produce spin-polarized currents in a Quantum Wire is crucial for spin-based electronics. Fortunately, the spin–orbit interaction can be exploited to deliver pure spin currents, without charge currents, that travel in one direction only.
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lasing from a single Quantum Wire
Applied Physics Letters, 2002Co-Authors: Yuhei Hayamizu, Hidefumi Akiyama, Masahiro Yoshita, Shinichi Watanabe, L N Pfeiffer, K W WestAbstract:A laser with an active volume consisting of only a single-Quantum Wire in the one-dimensional (1D) ground state is demonstrated. The single Wire is formed Quantum mechanically at the T-shaped intersection of a 14 nm Al0.07Ga0.93As Quantum well and a 6 nm GaAs Quantum well, and is embedded in a 1D single-mode optical waveguide. We observe single-mode lasing from the Quantum-Wire ground state by optical pumping. The laser operates from 5 to 60 K, and has a low threshold pumping power of 5 mW at 5 K.
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lasing from a single Quantum Wire
arXiv: Materials Science, 2002Co-Authors: Yuhei Hayamizu, Hidefumi Akiyama, Masahiro Yoshita, Shinichi Watanabe, L N Pfeiffer, K W WestAbstract:A laser with an active volume consisting of only a single Quantum Wire in the 1-dimensional (1-D) ground state is demonstrated. The single Wire is formed Quantum-mechanically at the T-intersection of a 14 nm Al_{0.07}Ga_{0.93}As Quantum well and a 6 nm GaAs Quantum well, and is embedded in a 1-D single-mode optical waveguide. We observe single-mode lasing from the Quantum Wire ground state by optical pumping. The laser operates from 5 to 60 K, and has a low threshold pumping power of 5 mW at 5 K.
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four terminal resistance of a ballistic Quantum Wire
Nature, 2001Co-Authors: R De Picciotto, L N Pfeiffer, H L Stormer, K W Baldwin, K W WestAbstract:The electrical resistance of a conductor is intimately related to the relaxation of the momentum of charge carriers. In a simple model, the accelerating force exerted on electrons by an applied electric field is balanced by a frictional force arising from their frequent collisions with obstacles such as impurities, grain boundaries or other deviations from a perfect crystalline order1. Thus, in the absence of any scattering, the electrical resistance should vanish altogether. Here, we observe such vanishing four-terminal resistance in a single-mode ballistic Quantum Wire. This result contrasts the value of the standard two-probe resistance measurements of h/2e2≈ 13 kΩ. The measurements are conducted in the highly controlled geometry afforded by epitaxial growth onto the cleaved edge of a high-quality GaAs/AlGaAs heterostructure. Two weakly invasive voltage probes are attached to the central section of a ballistic Quantum Wire to measure the inherent resistance of this clean one-dimensional conductor.
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experimental evidence for resonant tunneling in a luttinger liquid
Physical Review Letters, 2000Co-Authors: O M Auslaender, L N Pfeiffer, R De Picciotto, K W Baldwin, Amir Yacoby, K W WestAbstract:We have measured the low-temperature conductance of a one-dimensional island embedded in a single mode Quantum Wire. The Quantum Wire is fabricated using the cleaved edge overgrowth technique and the tunneling is through a single state of the island. Our results show that while the resonance line shape fits the derivative of the Fermi function the intrinsic linewidth decreases in a power law fashion as the temperature is reduced. This behavior agrees quantitatively with Furusaki's model for resonant tunneling in a Luttinger liquid.
H Weman - One of the best experts on this subject based on the ideXlab platform.
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high internal Quantum efficiency narrow linewidth ingaas gaas algaas Quantum Wire light emitting diodes
Applied Physics Letters, 2002Co-Authors: H Weman, L Sirigu, Klaus Leifer, Amit Rudra, K F Karlsson, Eli KaponAbstract:High internal Quantum efficiency (∼60%), narrow linewidth (as narrow as 14 meV) exciton emission at room temperature has been obtained using strained InGaAs V-groove Quantum Wire (QWR) light-emitting diodes (LEDs). The high efficiency is achieved with the aid of selective carrier injection through self-ordered AlGaAs vertical Quantum wells (VQWs), where the VQWs are separated from the InGaAs QWRs by thin GaAs spacer layers in order to reduce nonradiative recombination and inhomogeneous alloy broadening. Evidence for excitonic recombination in these LEDs up to RT is provided by measurements of the emission energy shifts at high magnetic fields.
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efficient narrow linewidth emission from ingaas algaas v groove Quantum Wire light emitting diodes
International Conference on Indium Phosphide and Related Materials, 2002Co-Authors: H Weman, L Sirigu, Klaus Leifer, K F Karlsson, Alok Rudra, Eli KaponAbstract:We have succeeded to achieve highly efficient, narrow linewidth electroluminescence (EL) at room temperature from strained InGaAs Quantum Wire (QWR) light-emitting diodes (LEDs). The internal Quantum efficiency is estimated to be as high as 60% for a single layer, 500-nm-pitch V-groove In/sub 0.15/Ga/sub 0.85/As QWR array LED, emitting at 1.29 eV (/spl lambda/ = 960 nm) with a linewidth as narrow as 14 meV. The high efficiency is achieved with the aid of selective carrier injection directly into the QWRs through self-ordered AlGaAs vertical Quantum wells (VQWs), where the VQWs were separated from the InGaAs QWRs by thin GaAs spacer layers in order to reduce nonradiative recombination and inhomogeneous alloy broadening.
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efficient narrow linewidth excitonic emission at room temperature from gaas algaas v groove Quantum Wire light emitting diodes
Applied Physics Letters, 2001Co-Authors: H Weman, Amit Rudra, M A Dupertuis, E Martinet, Eli KaponAbstract:We report on efficient, narrow linewidth exciton recombination in GaAs/AlGaAs V-groove Quantum Wire light-emitting diodes at room temperature. The high efficiency is due to a selective carrier injection mechanism resulting in an estimated internal Quantum efficiency of ∼20% with an electroluminescence (EL) linewidth as narrow as 15 meV. The thermal broadening contribution to the linewidth is 6 meV due to exciton scattering with optical phonons. An analysis of the EL peak shift in a magnetic field points out the typical superlinear behavior of the excitonic binding energy for a Quantum Wire.
