C2 and CN dynamics and pulsed laser deposition of CNx films

The time-resolved optical emission studies of laser ablated carbon plasma in nitrogen ambient are carried out to understand the dynamic of formation of C-2 and CN for depositing quality thin films. An optimum formation of C-2 is observed at 3 mm from the target surface and 350 ns after the initiation of plasma. However, CN is formed at comparatively larger distance, 4 mm, and larger delay (850 ns). The expanding plasma plume splits/bifurcates into slow and fast moving two distinct components, with the faster components further splitting up at later times (>350 ns) into two components. The estimated plume front velocity from plume imaging in the nitrogen ambient of 1.2 mbars at a delay of 100 ns is 3.8x10(6) cm/s, consistent with spectroscopic measurement similar to 3.0x10(6) cm/s. The CNx thin films deposited by pulsed laser deposition technique are characterized by x-ray diffraction, atomic force microscopy, and Raman spectroscopy. The high I-D/I-G ratio and peak position shift of G band to lower values in the films deposited for longer time indicates the high incorporation of nitrogen and increasing CN concentration within the film.