  We investigate the possibility of realizing a loophole-free violation of
Bell's inequality using deterministic single-photon sources. We provide a
detailed analysis of a scheme to achieve such violations over long distances
with immediate extensions to device-independent quantum key distribution. We
investigate the effect of key experimental imperfections that are unavoidable
in real-world single-photon sources including the finite degree of photon
indistinguishability, single-photon purity, and the overall source efficiency.
We benchmark the performance requirements to state-of-the-art deterministic
single-photon sources based on quantum dots in photonic nanostructures and find
that experimental realizations appear to be within reach. We also evaluate the
requirements for a post-selected version of the protocol, which relaxes the
demanding requirements with respect to the source efficiency.
