0000000000365578

AUTHOR

F. Alsina

showing 5 related works from this author

Dynamic carrier distribution in quantum wells modulated by surface acoustic waves

2001

We have investigated the dynamics of photogenerated carriers under surface acoustic wave (SAW) fields in GaAs quantum wells using spatially and time-resolved photoluminescence (PL). The frequency and phase of the PL oscillations under a SAW yield information about the carrier distribution and the band-gap modulation induced by the SAW. We directly prove that the transport properties of the carriers ultimately control their distribution, storage and, subsequent recombination in the modulated potential.

Surface (mathematics)PhysicsYield (engineering)Photoluminescencebusiness.industrySurface acoustic wavePhase (waves)Acoustic waveCondensed Matter::Mesoscopic Systems and Quantum Hall EffectCondensed Matter::Materials ScienceModulationOptoelectronicsbusinessQuantum well
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Modulation of the electronic properties of GaN films by surface acoustic waves

2003

We report on the interaction between photogenerated electron-hole pairs and surface acoustic waves (SAW) in GaN films grown on sapphire substrates. The spatial separation of photogenerated carriers by the piezoelectric field of the SAW is evidenced by the quenching of the photoluminescence (PL) intensity. The quenching levels in GaN are significantly smaller than those measured in GaAs under similar conditions. The latter is attributed to the lower exciton ionization efficiency and carrier separation probabilities mediated by the piezoelectric effect. The PL spectra also evidence energy shifts and broadenings of the electronic transitions, which are attributed to the band gap modulation by …

PhotoluminescenceMaterials scienceIII-V semiconductorsSurface acoustic wavesBand gapExcitonRadiation quenchingGeneral Physics and AstronomySemiconductor thin filmsCondensed Matter::Materials Science:FÍSICA [UNESCO]IonizationPiezoelectric semiconductorsPhotoluminescenceQuenchingbusiness.industryUNESCO::FÍSICAWide-bandgap semiconductorGallium compoundsAcoustic waveCondensed Matter::Mesoscopic Systems and Quantum Hall EffectWide band gap semiconductorsGallium compounds ; III-V semiconductors ; Wide band gap semiconductors ; Surface acoustic waves ; Semiconductor thin films ; Photoluminescence ; Radiation quenching ; Piezoelectric semiconductors ; Excitons ; Energy gapEnergy gapSapphireOptoelectronicsExcitonsbusiness
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Microscopic carrier dynamics in quantum wells modulated by high-frequency lateral fields

2002

Abstract We have investigated the dynamics of photogenerated carriers in GaAs quantum wells under the influence of high-frequency fields produced by metal gratings and by surface acoustic waves (SAW's) using spatially and time-resolved photoluminescence (PL). The frequency and phase of the PL oscillations induced by the high-frequency field yield information about the spatial distribution of the carriers and, in the case of SAW's, about the band-gap modulation induced by the SAW strain.

PhysicsPhotoluminescenceYield (engineering)Field (physics)Condensed matter physicsPhase (waves)Acoustic waveCondensed Matter::Mesoscopic Systems and Quantum Hall EffectCondensed Matter PhysicsAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic MaterialsCondensed Matter::Materials ScienceModulationCarrier dynamicsQuantum wellPhysica E: Low-dimensional Systems and Nanostructures
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Spatiotemporal carrier dynamics in quantum wells under surface acoustic waves

2004

We present a theoretical study of transport and recombination of electrons and holes in quantum wells under the piezoelectric field induced by a surface acoustic wave (SAW). Our model calculations, which include free carriers and excitons in the framework of the drift-diffusion equations, describe the spatial and time dependences of the photoluminescence intensity on excitation density and SAW amplitude, and show overall agreement with recent microphotoluminescence experiments performed on GaAs/(Al,Ga)As quantum wells and quantum wires.

PhysicsElectron mobilityPhotoluminescenceCondensed matter physicsField (physics)Condensed Matter::OtherSurface acoustic waveAcoustic waveElectronCondensed Matter::Mesoscopic Systems and Quantum Hall EffectCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsCondensed Matter::Materials ScienceQuantumQuantum wellPhysical Review B
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Focusing of surface-acoustic-wave fields on (100) GaAs surfaces

2003

Focused surface-acoustic waves (SAWs) provide a way to reach intense acoustic fields for electro- and optoacoustic applications on semiconductors. We have investigated the focusing of SAWs by interdigital transducers (IDTs) deposited on (100)-oriented GaAs substrates. The focusing IDTs have curved fingers designed to account for the acoustic anisotropy of the substrate. Different factors that affect focusing, such as the aperture angle and the configuration of the IDT fingers, were systematically addressed. We show that the focusing performance can be considerably improved by appropriate choice of the IDT metal pads, which, under appropriate conditions, create an acoustic waveguide within t…

Materials sciencebusiness.industrySurface acoustic waveFísicaGeneral Physics and AstronomySubstrate (electronics)Ciència dels materialsCollimated lightFull width at half maximumOpticsSemiconductorTransducerVertical displacementbusinessAnisotropyJournal of Applied Physics
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