Formation of diamond-like carbon films and carbon foam by ultrafast laser ablation

The ultra-fast ablation of a graphite target using high repetition rate Nd: YAG lasers allows us to deposit two distinctly different carbonaceous struc tures, depending on the ambient Ar pressure: a diamond-like carbon film wit h the surface finish down to atomic level at a pressure below 0.1 Torr, and a fractal C nanofoam with air-like density and diamond-like resistivity at higher pressure. The experimental characterization of vapors and carbonace ous materials produced is presented and compared to the theoretical predict ions. The analysis of the formation conditions leads to the qualitative und erstanding of the formation mechanism for both C structures.