Cover Picture: Phys. Status Solidi C 11/2013


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GaN/AlN quantum dots are promising emitters for high temperature operation devices because of their large exciton binding energy and band-offsets. The incorporation of GaN quantum dots in AlN cavities exhibiting high quality factors and small mode volumes is of major interest for the observation of cavity quantum electrodynamic effects at high temperature. Yet, the realization of such nanocavities remains challenging due to the large sensitivity of scattering losses related to fabrication imperfections and to the difficulty to create a sufficient-depth air-gap below the cavity to efficiently confine the light. In their paper, Sergent et al. on pp. 1517–1520 detail a newly developed layer transfer technique to circumvent such limitations and allow for the fabrication of AlN ladderstructure photonic crystal nanocavity embedding GaN QDs. They show how both the fabrication technique and the nanocavity design can improve the experimental quality factor, and they report on the highest quality factor obtained in an active group-III nitride semiconductor nanocavity, Q = 6900. The cover page shows a schematical view of the final nanobeam cavity structure and a micro-photoluminescence spectrum of the fundamental, first-order and second-order cavity modes that exhibit high quality factors.