InAs Quantum Dot Arrays Decorating the Facets of GaAs Nanowires

InAs quantum dot arrays are obtained on GaAs nanowire facets by molecular beam epitaxy. The GaAs nanowires are first grown by the gallium-assisted catalyst-free method. Decoration of the nanowire facets with InAs quantum dots is achieved only when the facets are capped with an ultrathin AlAs layer, as demonstrated by atomic force, high-resolution electron microscopy, and energy-dispersive X-ray spectroscopy line scans. The excitation of single and double excitons in the quantum dots are demonstrated by low-temperature photoluminescence spectroscopy realized on the single nanowires. This new type of heterostructures opens a new avenue to the fabrication of highly efficient single-photon sources, novel quantum optics experiments, as well as the realization of intermediate-band nanowire solar cells for third-generation photovoltaics.

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Anna Fontcuberta i Morral, Emanuele Uccelli
2010
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https://infoscience.epfl.ch/record/164060?ln=en

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Related concepts (2)

Nanowire

A nanowire is a nanostructure in the form of a wire with the diameter of the order of a nanometre (10−9 metres). More generally, nanowires can be defined as structures that have a thickness or diameter constrained to tens of nanometers or less and an unconstrained length. At these scales, quantum mechanical effects are important—which coined the term "quantum wires". Many different types of nanowires exist, including superconducting (e.g. YBCO), metallic (e.g. Ni, Pt, Au, Ag), semiconducting (e.g.

Quantum dot

Quantum dots (QDs) – also called semiconductor nanocrystals, are semiconductor particles a few nanometres in size, having optical and electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology and materials science. When the quantum dots are illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band.