Properties of amorphous carbon nitride prepared by RF reactive sputtering

Abstract

The local microstructure and optical and electrical properties were investigated of amorphous carbon nitride (a-CN) films deposited by reactive radio-frequency (RF) sputtering. Two series prepared in nitrogen or in a nitrogen and argon mixture were studied. The optical properties were investigated by transmittance/reflectance and photothermal deflection spectroscopies. Combined infrared measurements and Raman scattering spectroscopies were used to investigate the microstructure of a-CN films in terms of nitrogen incorporation within the films and C sp ² content. These experiments were completed by dark electrical conductivity measurements performed in coplanar configuration in the temperature range 50–450 K. The films exhibit semiconductor behaviour and the temperature dependence suggests two types of conduction. An increase in nitrogen incorporation induces an increase with clustering of sp ² phase replacing C=C olefinic groups with aromatic groups.

Acknowledgements

We wish to thank Dr G. Fanchini and Prof. A. Tagliaferro for providing samples and discussions.