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by Plasma Enhanced Chemical Vapor Deposition (PECVD)


Fundamental research throughout the last twenty years has demonstrated the spectacular modifications of the fundamental optoelectronic material properties in nanoscaled particles and structures. In recent years  these properties have been introduced into applied sciences or more practically in industrially usable products and processes. Especially the optoelectronic, magnetic and electrochemical properties of nanoparticles improve semiconductor or catalyst performance by several orders of magnitude due to  inherently different physical properties appearing at the nanometric scale.

In PECVD an organo-metallic precursor like Ferrocene Fe(C5H5)2 is exposed to a plasma in a vacuum that dissociates the molecule and creates radicals at high density. These radicals start nucleation, grow and coagulate in the gas phase thus creating nanoparticles, which can be captured in liquids or deposited onto substrates.

Iron nanoparticles captured in glycerin or silicon oil are used as catalysts, hematite nanostructures Fe2O3 on glass substrates are used for photo-electro-chemical water splitting (a subsequent project is dedicated to the production of hydrogen), i.e. for energy storage via the hydrogen cycle. The increase in catalytic performance of these nanoparticles could be applied for various catalytic processes, for example in purely chemical splitting of water or alcaline electrolysis in the « power2gas » projects.

SEM image showing nanocolumns of hematite (FexOy)
produced by the PECVD process

Depending on the deposition conditions the nanoparticles of about 50nm diameter form agglomerates which grow in very porous structures
on the substrate