Photoluminescence properties of multiple stacked planes of GaN/AlN quantumdots studied by near-field optical microscopy

We have studied the photoluminescence properties of GaN quantum dots with s ubmicrometre lateral resolution by means of near-field scanning optical mic roscopy. The instrument operated at room temperature and was implemented fo r near-ultra-violet spectroscopy in the illumination-mode configuration. Th e analysed sample consisted of several stacked planes of GaN/AIN quantum do ts grown by molecular beam epitaxy on Si(111) substrate. The photoluminesce nce maps showed islands in the micrometre range emitting at different wavel engths, confirming the atomic force microscopy studies on the morphology of similar uncapped samples.