  We demonstrate on-chip generation of indistinguishable photons based on a
nanowire quantum dot. From a growth substrate containing arrays of
positioned-controlled single dot nanowires, we select a single nanowire which
is placed on a SiN waveguide fabricated on a Si-based chip. Coupling of the
quantum dot emission to the SiN waveguide is via the evanescent mode in the
tapered nanowire. Post-selected two-photon interference visibilities using
continuous wave excitation above-band and into a p-shell of the dot were 100%,
consistent with a single photon source having negligible multi-photon emission
probability. Visibilities over the entire photon wavepacket, measured using
pulsed excitation, were reduced by a factor of 5 when exciting quasi-resonantly
and by a factor of 10 for above-band excitation. The role of excitation timing
jitter, spectral diffusion and pure dephasing in limiting visibilities over the
temporal extent of the photon is investigated using additional measurements of
the coherence and linewidth of the emitted photons.
