Cavity-enhanced radiative emission rate in a single-photon-emitting   diode operating at 0.5 GHz
  We report the observation of a Purcell enhancement in the electroluminescence decay rate of a single quantum dot, embedded in a microcavity light-emitting-diode structure. Lateral confinement of the optical mode was achieved using an annulus of low-refractive-index aluminium oxide, formed by wet oxidation. The same layer acts as a current aperture, reducing the active area of the device without impeding the electrical properties of the p-i-n diode. This allowed single photon electroluminescence to be demonstrated at repetition rates up to 0.5 GHz. 
David J. P. Ellis, Anthony J. Bennett, Samuel J. Dewhurst, Christine   A. Nicoll, David A. Ritchie and Andrew J. Shields