The ability to achieve near-unity light-extraction efficiency is necessary for a truly deterministicsingle-photon source. The most promising method to reach such high efficiencies is basedon embedding single-photon emitters in tapered photonic waveguides defined by top-downetching techniques. However, light-extraction efficiencies in current top-down approachesare limited by fabrication imperfections and etching-induced defects. The efficiency is furthertempered by randomly positioned off-axis quantum emitters. Here we present perfectlypositioned single quantum dots on the axis of a tailored nanowire waveguide using bottom-upgrowth. In comparison to quantum dots in nanowires without waveguides, we demonstrate a24-fold enhancement in the single-photon flux, corresponding to a light-extraction efficiency of42%. such high efficiencies in one-dimensional nanowires are promising to transfer quantuminformation over large distances between remote stationary qubits using flying qubits withinthe same nanowire p–n junction.
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