InP quantum dots in pillar microcavities – mode spectra and single-photon emission

We have investigated mode spectra and single-photon emission from InP quantum dots in a pillar microcavity. Micropillars are fabricated by milling a planar AlAs/AlGaAs cavity with a focused ion beam, containing self assembled InP quantum dots embedded in AlGaInP barriers as the active medium. We performed micro-photoluminescence measurements to characterize the mode spectra and compared them with a theoretical model revealing excellent agreement. Quality factors up to 3700 were achieved. Furthermore almost background-free single-photon emission was verified by second-order photon auto-correlation measurements under pulsed excitation, yielding g⁽²⁾(0) values of 0.15.