Epitaxial graphene fabrication

Researchers at FORTH/ICE-HT have recently reported on a novel method for the fast, single-step epitaxial growth of large-area homogeneous few-layer graphene film on the surface of SiC(0001) using an infrared CO2 laser (10.6 μm) as the heating source (a). This method is cost-effective in that it does not necessitate SiC pre-treatment and/or high vacuum conditions, it operates at low temperature and proceeds in the time scale of few seconds. In this context, it provides a green solution to EG fabrication and a means to engineering graphene patterns on SiC by focused laser beams. Scalability to industrial level of this method appears to be realistic, in view of the high rate of CO2-laser induced graphene growth, the lack of strict sample–environment conditions, and the possibility for in situ patterning.

More recent progress encompasses the fabrication of 3D graphene, i.e. graphene spheres (b) using near-infrared pulsed laser sources (see image below; scale bar: 200 nm). Laser irradiation causes growth of epitaxial graphene on SiC within few milliseconds at ambient conditions. The fast grown graphene layers fold due to charging and/or strain effects, thus forming multishell homocentric graphene spheres of various sizes. Analysis of Raman spectra has revealed the graphene-like nature of the shells forming these 3D graphene spheres. Layer folding influences graphene properties including optical, electrical, thermal, magnetic, mechanical, and H2 storage. Our approach offers a fast, one-step, method towards fabricating spherical graphene nanostructures, with very high surface area, at ambient atmosphere.

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