Dynamics of long-living excitons in tunable potential landscapes

Gärtner, A.; Schuh, Dieter; Kotthaus, J. P.

doi:10.1016/j.physe.2005.12.036

Cited by 8 publications

(10 citation statements)

References 13 publications

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“…[18] Such indirect excitons have a long lifetime, which is electrically tunable and which reaches values of up to 30 µs. [20], [21] In contrast, the optical lifetime of direct excitons in quantum wells is shorter than 1 ns (for T = 5 K). As depicted in Fig.…”

Section: Introductionmentioning

confidence: 99%

Micropatterned electrostatic traps for indirect excitons in coupled GaAs quantum wells

et al. 2007

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We demonstrate an electrostatic trap for indirect excitons in a field-effect structure based on coupled GaAs quantum wells. Within the plane of a double quantum well indirect excitons are trapped at the perimeter of a SiO 2 area sandwiched between the surface of the GaAs heterostructure and a semitransparent metallic top gate. The trapping mechanism is well explained by a combination of the quantum confined Stark effect and local field enhancement. We find the one-dimensional trapping potentials in the quantum well plane to be nearly harmonic with high spring constants exceeding 10 keV/cm².

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Section: Introductionmentioning

confidence: 99%

Micropatterned electrostatic traps for indirect excitons in coupled GaAs quantum wells

et al. 2007

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“…1(a), electrons and holes of photogenerated excitons may rearrange in a way that they are spatially separated by the tunnel barrier between the GaAs-QWs. These indirect excitons have a lifetime of ∼ 300 ns (for perpendicular electric fields of ∼ 10 6 V/m), 12 while the lifetimes of direct excitons are in the order of 1 ns. 13 The excitonic drift of such indirect, long-living excitons is induced by applying a voltage U ∆ across a resistive top gate ( Fig.…”

mentioning

confidence: 99%

Drift mobility of long-living excitons in coupled GaAs quantum wells

Gärtner

Holleitner

Kotthaus

et al. 2006

Applied Physics Letters

121

136

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We observe high-mobility transport of indirect excitons in coupled GaAs quantum wells. A voltage-tunable in-plane potential gradient is defined for excitons by exploiting the quantum confined Stark effect in combination with a lithographically designed resistive top gate. Excitonic photoluminescence resolved in space, energy, and time provides insight into the in-plane drift dynamics. Across several hundreds of microns an excitonic mobility of > 10 5 cm 2 /eVs is observed for temperatures below 10 K. With increasing temperature the excitonic mobility decreases due to exciton-phonon scattering.

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“…A classical model describing the non-linear dynamics of such a high-density dipolar exciton gas compares well with the observed features [34]. To learn more about the dynamics of such dipolar excitons and to explore efficient ways of generating high densities of cold excitons, a prerequisite for BEC, we have started to study their motion in welldefined in-plane potential gradients caused by a spatial variation of the out-of-plane electric field [35,36]. In a drift experiment we use a resistive and transparent gate electrode to create a gradient in the electrostatic potential applied between the gate and the back electrode.…”

Section: Drift and Confinement Of Long-living Excitons In Double Quanmentioning

confidence: 75%

Manipulating luminescence in semiconductor nanostructures via field‐effect‐tuneable potentials

Kotthaus

2006

Physica Status Solidi (b)

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The luminescence properties of III -V quantum wells under the influence of field-effect-tuneable and laterally modulated potentials are reviewed. Large electric fields generated in the quantum well plane cause a modulation of the quantum well absorption via the Franz -Keldysh effect as well as a reversible separation of optically excited electron -hole pairs. The electron -hole pair separation by field effect can prolong the recombination lifetimes by many orders of magnitude and yields a controllably delayed reemission of luminescence radiation. Dynamic in-plane electric fields caused by the propagation of surface acoustic waves on piezoelectric heterostructures make possible spatially and temporarily delayed luminescence whereas a two-dimensional modulation of the electrostatic potential enables the delayed storage of optical images. Spatial modulation of the quantum confined Stark effect via the out-of-plane electric field is employed to realize tuneable excitonic traps and to study macroscopic transport of long-living, spatially indirect excitons in suitably designed double quantum wells. This is possibly paving the way for the observation of excitonic Bose -Einstein condensation in quantum well structures.

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Dynamics of long-living excitons in tunable potential landscapes

Cited by 8 publications

References 13 publications

Micropatterned electrostatic traps for indirect excitons in coupled GaAs quantum wells

Micropatterned electrostatic traps for indirect excitons in coupled GaAs quantum wells

Drift mobility of long-living excitons in coupled GaAs quantum wells

Manipulating luminescence in semiconductor nanostructures via field‐effect‐tuneable potentials

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