Fabrication et étude de nanocavités photoniques de nitrure d'élément III contenant des boîtes quantiques GaN pour la réalisation d'émetteurs UV intégrés sur silicium
Auteur / Autrice : | Sylvain Sergent |
Direction : | Fabrice Semond, Jean-Yves Duboz |
Type : | Thèse de doctorat |
Discipline(s) : | Physique |
Date : | Soutenance en 2010 |
Etablissement(s) : | Nice |
Ecole(s) doctorale(s) : | École doctorale Sciences fondamentales et appliquées (Nice ; 2000-....) |
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Résumé
This work deals with the insertion of GaN quantum dots (QDs) in (Al,Ga)N-based optical nanocavities for the realization of novel photonic devices operating in the near UV range (300-400 nm) at room temperature (RT). The originality of this work is the use of silicon substrates to circumvent the inertness of group-III nitride materials and facilitate the realization of free-standing nanocavities. The main drawback of this approach is that optically active hétérostructures have to be grown close to the silicon substrate, typically 50 nm above the hetero-interface, in order to fabricate single mode operation devices. We first study the growth of GaN / (Al,Ga) N QD stacks in thin épitaxié. We demonstrate the possibility to obtain a wide range of QD densities from 10 [puissance]8 cm -² to a few 10¹¹ cm -². Despite the vicinity of the silicon substrate interface, we evidence the good quality of optical properties and especially the limited photoluminescence temperature-dependence of such QD stacks. We the optimize the fabrication processes of free-standing nanocavities : microdisk resonators are obtained through a classical top-down approach whereas two-dimensional photonic crystal (2D PC) cavities and up to 6600 in microdisk resonators. Using such optical resonators, work is ongoing to demonstrate both RT lasing and Purcell effect at short wavelength.