OPTICAL STUDIES OF CARBON NITRIDE THIN-FILMS DEPOSITED BY REACTIVE PULSED-LASER ABLATION OF A GRAPHITE TARGET IN LOW-PRESSURE AMMONIA

We report the characteristics revealed through optical investigations (microscopic studies, optical and IR transmission) of the thin films d eposited by multipulse UV reactive laser ablation of a graphite target in 10(2) Pa ammonia. We observe that the films deposited at room temp erature contain a mixture of carbon bonded to nitrogen in various conf igurations including the triple one and have a large optical band gap. On the other hand, the films deposited at 320 degrees C have a lower content in nitrogen. We present evidence of C-N bonds with lower charg e transfer. The layers are non-uniform and have a significantly narrow er optical band gap. We consider that this difference is due to the de sorption by heating of the highly reactive CN and CNH radicals. (C) 19 98 Elsevier Science S.A. All rights reserved.