Fine tuning of quantum-dot pillar microcavities by focused ion beam milling

Abstract

The targeted fine tuning of semiconductor pillar microcavities by postfabrication focused ion beam milling is described for the example of ZnSe-based structures with CdSe quantum dots embedded. Using the sensitive dependence of the spectral position of the modes on the cavity diameter, the modes are precisely blueshifted by a reduction of the pillar diameter with an accuracy below 100nm. The microcavities can be tuned to match the emission energy of individual quantum dots at a certain temperature, which results in a strongly enhanced luminescence intensity of the dots.