Correlation of photothermal conversion on the photo-induced deformation of amorphous carbon nitride films prepared by reactive sputtering

The photo-induced deformation of hydrogen-free amorphous carbon nitride (a-CNx) films was investigated under visible-light illumination. The films gave rise to photothermal conversion by irradiation. In this study, we investigated the effects of thermal energy generated by irradiation on the deformation of a-CNx/ultrathin substrate bimorph specimens. The films were prepared on both ultrathin Si and SiO2 substrates by reactive radio-frequency magnetron sputtering from a graphite target in the presence of pure nitrogen gas. The temperature of the film on the SiO2 substrate increased as the optical band-gap of the a-CNx was decreased. For the film on Si, the temperature remained constant. The deformation degree of the films on Si and SiO2 substrates were approximately the same. Thus, the deformation of a-CNx films primarily induced by photon energy directly.