Cavity quantum electrodynamic (QED) effects are studied in semiconductor microcavities embedded with InGaAs
quantum dots. Evidence of weak coupling in the form of lifetime enhancement (the Purcell effect) and inhibition is
found in both oxide-apertured micropillars and photonic crystals. In addition, high-efficiency, low-threshold lasing is
observed in the photonic crystal cavities where only 2-4 quantum dots exist within the cavity mode volume and are not
in general spectrally resonant. The transition to lasing in these soft turn-on devices is explored in a series of nanocavities
by observing the change in photon statistics of the cavity mode with increasing pump power near the threshold.
An oxide aperture is used to confine optical modes in a micropillar structure. This method overcomes the limitations due to sidewall scattering loss typical in semiconductor etched micropillars. High cavity quality factors (<i>Q</i>) up to 48 000 are determined by external Fabry-Perot cavity scanning measurements, a significantly higher value than prior work in III-V etched micropillars. Measured <i>Q</i> values and estimated mode volumes correspond to a maximum Purcell factor figure of merit value of 72. A Purcell Factor of 2.5 is experimentally observed from a single quantum dot emitter coupled to a high <i>Q</i> cavity mode.