Optical properties of N-doped diamond-like carbon films synthesized by pulsed laser deposition

Abstract

Optical properties of nitrogen-doped diamond-like carbon films deposited by pulsed laser deposition at room temperature are investigated. Three series of diamond-like carbon films are prepared by KrF excimer laser ablation of graphite with assistance of different nitrogen sources. Series 1: nitrogen gas of 99.999% purity is applied to react with carbon species. Diamond-like carbon films with nitrogen content of ~0.5-1.7 at.% are prepared at different nitrogen gas pressures (10^-4-10^-1Pa). Series 2: a radical beam source is used for providing an atomic nitrogen beam. Diamond-like carbon films with nitrogen content of ~1.0-5.4 at.% are synthesized at nitrogen gas pressure of 10^-3-10^-2Pa. Series 3: a 3-cm ion source is employed for supplying an active nitrogen ion beam. Diamond-like carbon films with nitrogen content varying from 8.0 to 14.3 at.% are deposited. The optical properties of the synthesized diamond-like carbon films are characterized by ultraviolet-visible spectrometry. Investigation indicates that the different nitrogen sources have different effects on the optical properties of diamond-like carbon films.