C_(2) and CN dynamics and pulsed laser deposition of CN_(x) films

摘要

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 3.8 X 10~(6) cm/s, consistent with spectroscopic measurement approx3.0 X 10~(6) cm/s. The CN_(x) 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.