Nucleation and growth of amorphous carbon film on tungsten-implanted stainless steel substrates

Amorphous carbon (a-C) films were deposited on W-implanted (20 kV, 3 × 1017 ions cm− 2) and un-implanted steel substrates by plasma immersion ion implantation and deposition (PIII&D). The W implantation pretreatment changes the surface structure and impacts film nucleation. Consequently, the growth mechanism of the a-C film is altered resulting in different surface morphologies and roughnesses even though the films deposited on the un-implanted steel substrates possess similar a-C structures as revealed by Raman spectroscopy. The structural differences are probed by X-ray photoelectron spectroscopy and X-ray diffraction. Moreover, microstructural observations were carried out by transmission electron microscopy. A model based on the statistical formation theory is proposed to explain the growth of the a-C films on the implanted and un-implanted substrates.