  Quantum dots are both excellent single-photon sources and hosts for single
spins. This combination enables the deterministic generation of Raman-photons
-- bandwidth-matched to an atomic quantum-memory -- and the generation of
photon cluster states, a resource in quantum communication and
measurement-based quantum computing. GaAs quantum dots in AlGaAs can be matched
in frequency to a rubidium-based photon memory, and have potentially improved
electron spin coherence compared to the widely used InGaAs quantum dots.
However, their charge stability and optical linewidths are typically much worse
than for their InGaAs counterparts. Here, we embed GaAs quantum dots into an
$n$-$i$-$p$-diode specially designed for low-temperature operation. We
demonstrate ultra-low noise behaviour: charge control via Coulomb blockade,
close-to lifetime-limited linewidths, and no blinking. We observe high-fidelity
optical electron-spin initialisation and long electron-spin lifetimes for these
quantum dots. Our work establishes a materials platform for low-noise quantum
photonics close to the red part of the spectrum.
