Monolithic II-VI pillar microcavities made of ZnSSe and MgS∕ZnCdSe supperlattices have been fabricated by molecular-beam epitaxy and focused-ion-beam etching. Discrete optical modes of the pillar microcavities are studied in photoluminescence measurements. The optical modes are identified by means of calculations based on an extended transfer matrix method. Achievable Purcell factors well above 10 can be estimated from the measured quality factors and calculated mode volumes.

We present photoluminescence measurements on single InGaN quantum dots grown by metalorganic vapor phase epitaxy. The spatially and spectrally resolved luminescence properties of the single quantum dots were measured using low-temperature micro-photoluminescence spectroscopy. The observed sharp emission lines of the quantum dots were characterized by excitation density dependent measurements. They can easily be observed at temperatures up to 150 K.

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A novel two-step growth method for creating InGaN quantum dots (QDs) was developed by using a combination of an In x Ga 1-x N nucleation layer with a platelet structure and an In y Ga 1-y N formation layer with an indium content lower than that of the In x Ga 1-x N nucleation layer. The realized QDs were investigated by micro-photoluminescence measurements. We observed sharp emission lines at 4 K with a spectral width down to the spectral resolution limit of the experimental setup of 0.17 meV. This growth concept is discussed in comparison with conventional growth methods.