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 / L. Ravagnan; P. Piseri; M. Bruzzi; S. Miglio; G. Bongiorno; A. Baserga; C.S. Casari; A. Li Bassi; C. Lenardi; Y. Yamaguchi; T. Wakabayashi; C.E. Bottani; P. Milani. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - STAMPA. - 98:(2007), pp. 216103-1-216103-4. [10.1103/PhysRevLett.98.216103]

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

BRUZZI, MARA;MIGLIO, STEFANIA;
2007

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.
2007
98
216103-1
216103-4
L. Ravagnan; P. Piseri; M. Bruzzi; S. Miglio; G. Bongiorno; A. Baserga; C.S. Casari; A. Li Bassi; C. Lenardi; Y. Yamaguchi; T. Wakabayashi; C.E. Bottani; P. Milani
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/341177
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