However, this would mean that most PLD carbon films would be double structured, which is not the case. Budai et al. synthesized carbon films in methane or hydrogen (pressures ranging between 10−7 and 0.5 mbar) using an ArF laser source, but observed no such double layering. In their case, the ambient influenced just the thickness of the films, the methane ambient favoring synthesis of 1.5 times thicker layers than in the case of hydrogen ambient. Modabber et al. synthesized DLC films in vacuum, applying a constant number of pulses and changing only the substrate temperature between 100 and 300 °C. They observed that by increasing the substrate temperature, the ratio of sp2 bonding augmented and the mechanical properties decreased. However, no double layers were reported, and this is in agreement with our findings that in vacuum the soft top layer is extremely thin (few nm only). Growth of DLC films by PLD in inert gases, such as He and Ar, also produces monolayers.