Amorphous carbon thin films

Amorphous carbon thin films are some of the toughest coatings available on the market being used in cutting bits, hard drives, razors and to protect car engines.

Amorphous carbon does not have crystalline structure like graphite or diamond, but on short distances the structure most closely resembles diamond, making the coating incredibly strong, dense and durable.

The nanostructure depends on the ratio of graphitic (sp2) diamond like bonding (sp3) as well as the amount of hydrogen.

Our fundamental insights include;

• The first computer simulations of how tetrahedral amorphous carbon is formed using ab-initio molecular dynamics.

• The development of the EDIP forcefield in 2000, which has been powerful in describing many other different carbon materials.

• The peening mechanism was proposed to explain the formation mechanism of tetrahedral amorphous carbon.

Experimentally, we have developed equipment a custom vacuum system for physical vapour deposition. The high-power impulse magnetron sputtering (HiPIMS) is used to deposit amorphous carbon thin films with high concentration of tetrahedral carbons.

This system has also been used to deposit high-quality metal coatings that are being developed to stop hydrogen permeability through pipes for the hydrogen economy.

A profilometer is available to measure the thickness of coatings and their roughness at the sub-nanometre scale

Marks, N. A. (2010). Amorphous carbon and related materials. Computer-Based Modeling of Novel Carbon Systems and Their Properties: Beyond Nanotubes, 129-169.

Marks, N. A. (1997). Evidence for subpicosecond thermal spikes in the formation of tetrahedral amorphous carbon. Physical Review B, 56(5), 2441.

Marks, N. A., McKenzie, D. R., Pailthorpe, B. A., Bernasconi, M., & Parrinello, M. (1996). Microscopic structure of tetrahedral amorphous carbon. Physical review letters, 76(5), 768.

Tucker, M. D., Ganesan, R., McCulloch, D. G., Partridge, J. G., Stueber, M., Ulrich, S., ... & Marks, N. A. (2016). Mixed-mode high-power impulse magnetron sputter deposition of tetrahedral amorphous carbon with pulse-length control of ionization. Journal of applied physics, 119(15).

Tucker, M. D., Putman, K. J., Ganesan, R., Lattemann, M., Stueber, M., Ulrich, S., ... & Marks, N. A. (2017). The behaviour of arcs in carbon mixed-mode high-power impulse magnetron sputtering. Journal of Physics D: Applied Physics, 50(14), 145205.