The authors have characterized in air, carbon films of thickness around 1 nm on Si (100) grown in ultrahigh vacuum conditions by pulsed laser vaporization of a graphite target. The substrate preparation procedure was chosen on the basis of minimizing surface roughness as viewed from scanning tunneling microscope topographic images. Atomic resolution images taken in the constant height mode revealed different atomic ordered configurations. A hexagonal structure was preferentially observed with a lattice parameter of 2.4 ű0.2 Å and extending up to 140×140 Å2. Also, a square lattice, 2.0 ű0.2 Å side, was imaged coexisting with the hexagonal one. Other structures were found which could be related with the substrate.I‐Vspectroscopy was performed in these films showing ap‐type rectifying behavior and an electronic band gap.