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GaN wire based blue LEDs : from growth to device

Vendredi 25 octobre 2013 15:30 - Duree : 1 heure
Lieu : Room 500 - 501, Central Building, ESRF - 6 Rue Jules Horowitz - Grenoble

Orateur : Damien SALOMON (CEA/Grenoble)

I will talk about the realization by metal organic vapor phase epitaxy of blue light emitting diodes based on GaN wires grown on Si(111) with a focus on understanding the structural and optical properties of InGaN/GaN core/shell heterostructures grown around the wires. The MOVPE growth of –c oriented GaN wires on sapphire will be presented first. We demonstrate that the injection of silane during the growth induces the formation of a SiNx passivation layer around the GaN wires, preventing their lateral expansion. The silane flow can be stopped after a certain time without modifying the wire geometry. This phenomenon is used to control the position of the InGaN/GaN multiple quantum well shells along the wires. The wire growth on sapphire is then transferred to silicon substrate thanks to the deposition of a thin AlN buffer layer prior to the wire growth and the epitaxial relationships between the different layers is analyzed by X-ray diffraction. The deposition of InGaN/GaN heterostructures on the wires is then performed using typical 2D growth conditions. Several types of quantum wells grown on different facets of the wire surface are observed. These different families emit light at different wavelengths that have been indexed thanks to cathodoluminescence mapping. The non-polar characteristic of the MQWs grown on the side facets of the wires is then evidenced by comparing experimental results to simulation of structures grown on polar (c) and non-polar (m) planes using the 8x8 band k.p theory for electron and hole masses. Finally, complete LED structures have been deposited on GaN wires by MOVPE and blue electroluminescence at 450 nm has been measured on single wires and assemblies of wires on Si(111).

Contact : eva.jahn@esrf.freva.jahn@esrf.fr

Discipline évènement : (Physique)
Entité organisatrice : (ESRF)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire ESRF)
Site de l'évènement : Polygone scientifique

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