Fe-N Thin Films Prepared by Excimer Laser Ablation

Fe-N films were deposited on glass substrates at room temperature using a pulsed KrF excimer laser (wavelength 248 nm, pulse width 27 ns). The film composition and structure depend on the ambient N2 pressure, the laser pulse energy, and the repetition rate. In order to understand the interaction between light-emitting ablated particles produced by excimer laser ablation of Fe and ambient N2 gas, the dynamics of ablated plumes were investigated by means of a high-speed framing streak camera and time-resolved emission spectroscopy. Two distinct components of ablated particles were observed. One consisted of a spherical plume with an average velocity of over 100 km/s, which was observed for about 300 ns from the laser irradiation. The other consisted of a columnar plume with a maximum velocity of 22 km/s, which was observed for 1 to 10 ¿s. The velocity of the Fe radicals depends on the N2 pressure, which contributes to formation of the Fe-N film.