a b s t r a c tNitrogen-doped amorphous carbon thin films (a-CN x ) were prepared on silicon substrate by pulsed laser deposition process using methane (CH 4 ) and nitrogen (N 2 ) as source gas. The electrical properties of a-CN x films changes with nitrogen concentration in the film structure. The intensity ratio of the D and G peak (I D /I G ) increases with higher nitrogen concentration, which means that sp 2 -clusters were formed in these films and is responsible for the enhancement of conductivity of the a-CN x films. We observed that the amorphous carbon (a-C) films becoming more graphitic in nature yielding higher conductivity/lower resistivity with increase of nitrogen concentration. Electron field emission result shows that the emission current density enhances with nitrogen doping that indicates the useful in electron field emission devices application.

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Diamond-like carbon (DLC) thin films are prepared using plasma enhanced chemical vapour deposition (PECVD) process at different bias voltage. We have studied their microstructural and electrical properties using Raman spectroscopy and current (I) – voltage (V) relationships. Electrical conductivity is gradually decreases with bias voltage as the films are becoming more and more diamond like carbon as observed from Raman spectroscopy results. Raman spectroscopy result shows that the ID/IG ratio gradually decreases indicating formation of more diamond like carbon films that responsible for the decrease of conductivity of the films. The full width half maximum of G peak increase with increase the bias voltage indicating the ring-like sp2 transforms to sp2 chains and raises the amount of sp3-chains. The structural disorder arises from the bond angle and bond length distortions in amorphous carbon films. Thus the structural disorder and mechanical properties such as hardness and elastic modulus increase with bias voltage.

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