Sticking probability of the CN( X2Σ +) radicals onto the hydrogenated amorphous carbon nitride films

Abstract

The sticking probability ( s) of the CN( X 2Σ +) radicals onto the hydrogenated amorphous carbon nitride ( a-CN x :H) films was determined by measuring the density of CN( X 2Σ +) in the gas phase, the flow speed, and the weight of a-CN x :H. The CN( X 2Σ +) radicals were produced by the dissociative excitation reaction of BrCN with the microwave discharge flow of Ar, and were observed by the laser induced fluorescence (LIF) spectroscopy of the CN( A 2Π i - X 2Σ +), 4–0, 5–1, and 7–2 bands. The LIF intensity was calibrated against Rayleigh scattering intensity by Ar atoms, from which the density of CN( X 2Σ +) was determined as 1.0 × 10 18–4.9 × 10 18 m − 3 depending on the pressure of Ar ( P Ar) as 0.4–0.7 Torr. The s value was in the range of 0.032–0.019 which was also dependent on P Ar. According to the IR observation of the a-CN x :H films, the P Ar-dependence of s was found to originate in the reactivity of the CN radicals on the film surface.