M. Karl, T. Beck, S. Li, H. Kalt, M. Hetterich

Appl. Phys. Lett. 92, 231105 (2008)

GaAs pyramids on top of GaAs/AlAs distributed Bragg reflectors (DBRs) are studied as candidates for microcavities with low mode volume. Photoluminescence spectra of single pyramids with embedded quantum dots show cavity modes with quality (Q-) factors of up to 700. Furthermore, to assess the complex mode structure in pyramids a finite-difference time-domain simulation with rotational symmetry is used to evaluate cavity modes in a cone on top of a DBR. A cone angle around 46° was identified for highest Q-factors. Based on our calculations, approaches to improve the light confinement are suggested which should result in microcavities with high Q-factors.