Quantum Light Emission from GaAs _x P _{1– x} Quantum Dots in Wurtzite GaP Nanowires

Tunable single-photon emitters in nanowires (NWs) are promising building blocks of compact and efficient quantum photonic devices. We report the vapor-liquid-solid growth of wurtzite (WZ) GaAs_xP_1-x (x = 0.7 and 0.9) quantum dots (QDs) embedded in defect-free WZ GaP NWs, showing high crystalline quality and emission in the 630-700 nm wavelength range. Power- and temperature-dependent microphotoluminescence (μ-PL) measurements show well-resolved single excitonic lines with fwhm < 2 meV up to 70 K. Band structure calculations allow effective modeling of the relation between QD size, alloy composition, and QD emission energy. Second-order autocorrelation measurements demonstrate high-purity single-photon emission, with g⁽²⁾(0) = 0.090 ± 0.001 under pulsed excitation at 5 K, and antibunching also under continuous-wave excitation, from 5 to 40 K. Time-resolved measurements reveal lifetimes shorter than one nanosecond. Our results show that WZ GaAs_xP_1-x QDs in GaP NWs have potential as wavelength-tunable quantum light emitters under relaxed cryogenic conditions.