Structural and optical investigation of nanostructures : from silicene to plasmonic gold nanoparticles

Orateur : Yves BORENSZTEIN (Institut des NanoSciences Paris, P6)

We will present an overview of some research conducted recently, concerning the growth, structure and reactivity of dif ferent nanostructured systems, mainly by STM, X-ray diffraction, X-ray photoemission and linear optical spectroscopies. The silicene, which is the counterpart of graphene for silicon, is an increasing field of investigation. Real-time monitoring of the growth of silicene on silver surfaces showed us that it is a complex process, due to high reactivity between silver and silicon. This prevents to obtain the electronic properties expected for self-standing silicene, as demonstrated by optical measurements. Gold or gold-based alloy nanoparticles supported on oxides exhibit interesting catalytic properties, particularly for oxidation reactions such as CO oxidation. We will present a real-time investigation of the formation of Au and Au-Cu particles on titanium oxide surface and of their reactivity upon CO and / or O2 exposure. We will also discuss the modifications of the plasmonic properties of gold nanoparticles under gas.

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