Spectroscopic analysis of photo-induced deformation of amorphous carbon nitride films

Abstract

Reversible photo-induced deformation of amorphous carbon nitride (a-CNx) films was investigated. The films were deposited at 400 and 600 °C on a rectangular shaped ultrathin SiO2 substrate by reactive radio frequency magnetron sputtering with graphite target and pure N2 gas. The amount of deformation change was estimated from bending curvature of a-CNx/SiO2 bimorph structure. For the film deposited at 400 °C, it bent toward the film side under illumination. Photo-induced deformation of the film estimated from the bending angle was observed in the excitation energy of 1.77 to 3.35 eV. The maximum deformation was observed under illumination of 2.6 eV which corresponds with π-π∗ bond of carbon nitride. In contrast, the deformation was hardly observed in the films deposited at 600 oC.The difference in these two films was probably due to difference in sp2 bonding and termination structures.