A spectroscopic and ab initio study of the formation of graphite and carbon nanotubes from thermal decomposition of silicon carbide.
We report an experimental and first-principles study of the thermal decomposition of 6H-SiC wafers, yielding graphite on the Si-terminated face and carbon nanotubes on the C-terminated face. The asymmetry of the carbon structure formation mechanisms is rationalized in terms of the different termination geometries of the opposite SiC faces. First-principles modeling reveals that horizontal, xr-delocalized carbon structures form on the Si-terminated face. The bonding network geometry of the C-terminated face favors instead the formation of vertically oriented carbon structures, which can be interpreted as nanotube lateral wall precursors.
INFM-DEMOCRITOS National Simulation Centre and Centre of Excellence for Nanostructured Materials, University of Trieste, Italy. glevita@units.it
Giacomo
G
Levita
Luca
L
Petaccia
Alessio
A
Comisso
Silvano
S
Lizzit
Rosanna
R
Larciprete
Andrea
A
Goldoni
Alessandro
A
De Vita