We report the production and characterization of a form of amorphous carbon with sp-sp2 hybridization (atomic fraction of sp hybridized species 20%) where the predominant sp bonding appears to be C C n cumulene. Vibrational and electronic properties have been studied by in situ Raman spectroscopy and electrical conductivity measurements. Cumulenic chains are substantially stable in high vacuum conditions for temperatures lower than 250 K and they influence the electrical transport properties of the sp-sp2 carbon through a self-doping mechanism by pinning the Fermi level closer to one of the mobility gap edges. Upon heating above 250 K the cumulenic species decay to form graphitic nanodomains embedded in the sp2 amorphous matrix thus reducing the activation energy of the material. This is the first example of a pure carbon system where the sp hybridization influences bulk properties.

Influence of cumulenic chains on the vibrational and electronic properties of sp/sp2 amorphous carbon

BASERGA, ANDREA;CASARI, CARLO SPARTACO;LI BASSI, ANDREA;BOTTANI, CARLO ENRICO;
2007-01-01

Abstract

We report the production and characterization of a form of amorphous carbon with sp-sp2 hybridization (atomic fraction of sp hybridized species 20%) where the predominant sp bonding appears to be C C n cumulene. Vibrational and electronic properties have been studied by in situ Raman spectroscopy and electrical conductivity measurements. Cumulenic chains are substantially stable in high vacuum conditions for temperatures lower than 250 K and they influence the electrical transport properties of the sp-sp2 carbon through a self-doping mechanism by pinning the Fermi level closer to one of the mobility gap edges. Upon heating above 250 K the cumulenic species decay to form graphitic nanodomains embedded in the sp2 amorphous matrix thus reducing the activation energy of the material. This is the first example of a pure carbon system where the sp hybridization influences bulk properties.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/517352
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