Motivated by the existence of inconsistencies in the literature, the self-organized nucleation of GaN nanowires on silicon substrate is re-investigated. Noticeably, the N polarity rather than the underlying micro-structure of the substrate is non-ambiguously evidenced as a requisite for triggering nanowire nucleation.

A side product of the systematic polarity analysis performed on nanowires is the discovery of inversion domains. They are shown to correlate with a specific luminescence at 3.45 eV, which brings a decisive answer to the controversial origin of this photoluminescence line reported for long in nanowires.

The growth of quantum heterostructures in nanowires spontaneously results in disk-like structures having photoluminescence properties deeply linked to the nanowire structure. In order to limit this dependence, the growth of dot-like heterostructures is proposed and their nucleation through a novel growth route is demonstrated.

At last, the measurement of diffusion lengths of charge carriers in GaN and AlN nanowires is used to probe the inner electronic potential landscape of nanowires.

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English : Vigipirate being applied, people who would like to attend this defence and have no CNRS badge should contact us at least 24h before so as to appear on the allowed entrance list.

Contact : auzellethomas@gmail.com ou bruno.daudin@cea.fr