Microcavity single-photon-emitting diode

We show that a planar semiconductor cavity can be used to enhance by a factor of ten the efficiency with which photons are collected from an electrically driven single InAs/GaAs quantum dot. Under a fixed bias we observe that the photon statistics change when the injection current is modified. The observed bunching of photons from the biexciton state can be explained by the presence of charged states or dark states within the quantum dot with lifetimes greater than 4 ns. Single-photon emission from both the exciton and biexciton states is demonstrated under pulsed electrical injection. (c) 2005 American Institute of Physics.