Pulsed laser deposition of amorphous carbon nitride thin films and their electrical properties

Abstract

Amorphous carbon nitride thin films were deposited by pulsed laser deposition combined with a nitrogen rf radical beam source. A structural characterization of the deposited films was performed using X-ray photoelectron and Raman-scattering spectroscopy. The Raman spectra showed that the dominant hybridization state of carbon atoms in the deposited film is sp2. N 1s electron spectra were deconvoluted into three components, N bonded to pyridine-like N and/or N-sp3C (N1), substitutional N in graphite (N2), and N-O and/or N-N (N3). The proportion of N1 increased with increasing N/C atomic ratio in the film. The electrical conductivity at room temperature decreased and the Tauc optical band gap increased with increasing N/C atomic ratio. The temperature dependence of the electrical conductivity indicated that electronic conduction occurred by variable range hopping between π electron localized states. The decrease in electrical conductivity with increasing N/C atomic ratio was caused by a strong π electron localization due to the increased proportion of N1.