Probing carrier dynamics in nanostructures by picosecond cathodoluminescence

Picosecond and femtosecond spectroscopy allow the detailed study of carrier dynamics in nanostructured materials. In such experiments, a laser pulse normally excites several nanostructures at once. However, spectroscopic information may also be acquired using pulses from an electron beam in a modern...

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Bibliographic Details
Published in:Nature 2005-11, Vol.438 (7067), p.479-482
Main Authors: Crottini, A, Sonderegger, S, Deveaud, B, Kapon, E, Ganière, J.-D, Merano, M, Baier, M. H, Pelucchi, E, Collin, S, Renucci, P, Malko, A
Format: Article
Language:English
Subjects:
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures
Electronic transport in multilayers, nanoscale materials and structures
Exact sciences and technology
Nanostructured materials
Optics
Physics
Quantum theory
Quantum wires
Semiconductors
Spectrum analysis
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Summary:Picosecond and femtosecond spectroscopy allow the detailed study of carrier dynamics in nanostructured materials. In such experiments, a laser pulse normally excites several nanostructures at once. However, spectroscopic information may also be acquired using pulses from an electron beam in a modern electron microscope, exploiting a phenomenon called cathodoluminescence. This approach offers several advantages. The multimode imaging capabilities of the electron microscope enable the correlation of optical properties (via cathodoluminescence) with surface morphology (secondary electron mode) at the nanometre scale. The broad energy range of the electrons can excite wide-bandgap materials, such as diamond- or gallium-nitride-based structures that are not easily excited by conventional optical means. But perhaps most intriguingly, the small beam can probe a single selected nanostructure. Here we apply an original time-resolved cathodoluminescence set-up to describe carrier dynamics within single gallium-arsenide-based pyramidal nanostructures with a time resolution of 10 picoseconds and a spatial resolution of 50 nanometres. The behaviour of such charge carriers could be useful for evaluating elementary components in quantum computers, optical quantum gates or single photon sources for quantum cryptography.
ISSN:0028-0836
1476-4687
1476-4679
DOI:10.1038/nature04298