Mangolini, Filippo Hilbert, James McClimon, J. Brandon Lukes, Jennifer R. Carpick, Robert W. Thermally Induced Structural Evolution of Silicon- and Oxygen-Containing Hydrogenated Amorphous Carbon: A Combined Spectroscopic and Molecular Dynamics Simulation Investigation Silicon- and oxygen-containing hydrogenated amorphous carbon (a-C:H:Si:O) coatings are amorphous thin-film materials composed of hydrogenated amorphous carbon (a-C:H), doped with silicon and oxygen. Compared to a-C:H, a-C:H:Si:O exhibits much lower susceptibility to oxidative degradation and higher thermal stability, making a-C:H:Si:O attractive for many applications. However, the physical mechanisms for this improved behavior are not understood. Here, the thermally induced structural evolution of a-C:H:Si:O was investigated in situ by X-ray photoelectron and absorption spectroscopy, as well as molecular dynamics (MD) simulations. The spectroscopy results indicate that upon high vacuum annealing, two thermally activated processes with a Gaussian distribution of activation energies with mean value <i>E</i> and standard deviation σ take place in a-C:H:Si:O: (a) ordering and clustering of sp<sup>2</sup> carbon (<i>E</i> ± σ = 0.22 ± 0.08 eV) and (b) conversion of sp<sup>3</sup>- to sp<sup>2</sup>-bonded carbon (<i>E</i> ± σ = 3.0 ± 1.1 eV). The experimental results are in qualitative agreement with the outcomes of MD simulations performed using a ReaxFF potential. The MD simulations also indicate that the higher thermal stability of a-C:H:Si:O compared to a-C:H (with similar fraction of sp<sup>2</sup>-bonded carbon and hydrogen content) derives from the significantly lower fraction of strained carbon–carbon sp<sup>3</sup> bonds in a-C:H:Si:O compared to a-C:H, which are more likely to break at elevated temperatures. sp 2 carbon;Molecular Dynamics Simulation Investigation Silicon;sp 2;a-C;Oxygen-Containing Hydrogenated Amorphous Carbon;Thermally Induced Structural Evolution;MD simulations 2018-02-12
    https://acs.figshare.com/articles/journal_contribution/Thermally_Induced_Structural_Evolution_of_Silicon-_and_Oxygen-Containing_Hydrogenated_Amorphous_Carbon_A_Combined_Spectroscopic_and_Molecular_Dynamics_Simulation_Investigation/5899249
10.1021/acs.langmuir.7b04266.s001