  We report recent progress toward on-chip single photon emission and detection
in the near infrared utilizing semiconductor nanowires. Our single photon
emitter is based on a single InAsP quantum dot embedded in a p-n junction
defined along the growth axis of an InP nanowire. Under forward bias, light is
emitted from the single quantum dot by electrical injection of electrons and
holes. The optical quality of the quantum dot emission is shown to improve when
surrounding the dot material by a small intrinsic section of InP. Finally, we
report large multiplication factors in excess of 1000 from a single Si nanowire
avalanche photodiode comprised of p-doped, intrinsic, and n-doped sections. The
large multiplication factor obtained from a single Si nanowire opens up the
possibility to detect a single photon at the nanoscale.
