Optical microcavities fabricated by DBR overgrowth of pyramidal-shaped GaAs mesas

Optical cavities have been fabricated by overgrowth of truncated GaAs pyramids with a distributed Bragg reflector. The success of this overgrowth depends strongly on the crystallographic orientation of the pyramid facets and shows best results for { 1 1 4 } A facets. In order to fabricate mesas with precisely such facets, a wet-chemical etching process including several selective etching steps has been established. To determine the optical properties of these resonators, InAs quantum dots have been used as an internal broad-band light source. The quality factors for optical modes have been determined to range up to 8000 and show a dependency on cavity width.