Effect of tungsten doping on laser ablation and graphitization of diamond-like nanocomposite films

Laser surface microstructuring of diamond-like nanocomposite (DLN) films is a promising technique to improve their properties. For industrial applications, UV excimer or IR lasers with high pulse repetition rate are commonly used. In this paper, we investigate the influence of metal (tungsten) doping of DLN film on the ablation and graphitization behavior of the films using KrF laser (lambda = 248 nm, tau = 20 ns) and Yb:Yag laser (lambda = 1030 nm, tau = 8 ps). The response is found to be sensitive to the laser wavelength and pulse duration. For UV nspulses, the ablation threshold is insensitive to W-doping, showing only a slight increase for the highest tungsten concentration of 27 at.%, while the ablation rate decreases. Conversely, an increase of tungsten content in the case of the irradiation by IR ps-pulses induces a drop in the ablation threshold and an increase in the ablation rate. The structural modification of the films is analyzed by Raman spectroscopy, which also allows us to estimate the thickness of a residual graphitized layer on the surface after laser irradiation. It is found that laser induced graphitization is stronger for doped DLN films after multipulse irradiation.

Automated summary

The study investigates the influence of tungsten doping on DLN films under different laser irradiation, finding that the ablation threshold and rate are influenced by laser wavelength and pulse width. Ablation threshold is insensitive to tungsten doping under UV laser, while it decreases and ablation rate increases under IR laser.