Nitridation of Nb surface by nanosecond and femtosecond laser pulses

Farha A. H., Ozkendir O. M., Koroglu U., UFUKTEPE Y., Elsayed-Ali H. E.

JOURNAL OF ALLOYS AND COMPOUNDS, vol.618, pp.685-693, 2015 (SCI-Expanded) identifier identifier


Niobium nitride samples were prepared by laser nitridation in a reactive nitrogen gas environment at room temperature using a Q-switched Nd:YAG nanosecond laser and a Ti:sapphire femtosecond laser. The effects of laser fluence on the formed phase, surface morphology, and electronic properties of the NbNx, were investigated. The samples were prepared at different nanosecond laser fluences up to 5.0 +/- 0.8 J/cm(2) at fixed nitrogen pressure of similar to 2.7 x 10(4) Pa formed NbNx with mainly the cubic delta-NbN phase. Femtosecond laser nitrided samples were prepared using laser fluences up to 1.3 +/- 0.3 mJ/cm(2) at similar to 4.0 x 10(4)Pa nitrogen pressure. Laser induced ripple patterns oriented parallel to the beam polarization were formed with spacing that increases with the laser fluence. To achieve a laser-nitrided surface with desired crystal orientation the laser fulence is an important parameter that needs to be properly adjusted. (C) 2014 Elsevier B.V. All rights reserved.