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New avenues to GaN technology

Vendredi 4 octobre 2013 14:00 - Duree : 1 heure
Lieu : CTRM Control Room, ESRF - 6 Rue Jules Horowitz - Grenoble

Orateur : Slava KACHKANOV (Diamond Light Source)

The III-nitride semiconductors (GaN, InN, AlN and their alloys) have become a subject of intense research in the past fifteen years due to the unique physical properties of these materials, which include a wide direct bandgap, remarkable mechanical strength and high melting temperatures, as well as their huge commercial utility. Nitride materials have revolutionized the optoelectronic industry, leading recently to robust, compact and energy efficient all-solid state light sources covering the broad spectral range from infra-red to ultraviolet. In this talk I will present recent results on nitrides obtained by X-ray microdiffraction and Optically Detected X-ray Magnetic Circular Dichroism (XMCD). X-ray microdiffraction in three-dimensions has been used to characterise GaN microcrystals grown on silicon by a novel process named Evolutionary Selection Selective Area Growth (ES-SAG). The ES-SAG process is based on a mechanism defined as evolutionary selection where the fastest-growing crystal grains overtake their slower growing neighbours and become dominant in the growth channel which filters misaligned grains thus forming polycrystalline GaN into nearly mono-crystalline layer. Utilizing high resolution in both direct and reciprocal spaces, structural dynamics of GaN microcrystals has been unravelled in growth structures of different dimensions. This is a step forward towards advanced hybrid GaN/silicon electronic devices. The use of X-ray Excited Optical Luminescence (XEOL) for detection of XMCD allowed us to probe induced magnetic moment of Eu3+ ions in GaN. The induced magnetic moment is associated with the 7F2 final state of 5D0→7F2 optical transitions emitting at 622 nm which can be excited optically or electrically. This opens up the perspective for controlling magnetic moment electrically or optically in technologically established material.

Contact : isabelle.combe@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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