  Single-photons are key elements of many future quantum technologies, be it
for the realisation of large-scale quantum communication networks for quantum
simulation of chemical and physical processes or for connecting quantum
memories in a quantum computer. Scaling quantum technologies will thus require
efficient, on-demand, sources of highly indistinguishable single-photons.
Semiconductor quantum dots inserted in photonic structures are ultrabright
single photon sources, but the photon indistinguishability is limited by charge
noise induced by nearby surfaces. The current state of the art for
indistinguishability are parametric down conversion single-photon sources, but
they intrinsically generate multiphoton events and hence must be operated at
very low brightness to maintain high single photon purity. To date, no
technology has proven to be capable of providing a source that simultaneously
generates near-unity indistinguishability and pure single photons with high
brightness. Here, we report on such devices made of quantum dots in
electrically controlled cavity structures. We demonstrate on-demand, bright and
ultra-pure single photon generation. Application of an electrical bias on
deterministically fabricated devices is shown to fully cancel charge noise
effects. Under resonant excitation, an indistinguishability of
$0.9956\pm0.0045$ is evidenced with a $g^{2}(0)=0.0028\pm0.0012$. The photon
extraction of $65%$ and measured brightness of $0.154\pm0.015$ make this source
$20$ times brighter than any source of equal quality. This new generation of
sources open the way to a new level of complexity and scalability in optical
quantum manipulation.
