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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.

The effects of chemical bonding states on the electrical properties of hydrogen-free amorphous carbon nitride (a-CN x ) films were reported. a-CN x films were prepared by reactive RF magnetron sputtering at various deposition temperatures. The electrical conductivity of the a-CN x films increased with increasing deposition temperature because of the predominant sp 2 C-C bonding sites. Their conductivity increased by almost one order of magnitude with a 25% decrease in the fraction of the N-sp 3 C bonding state. It was found that the fraction of the N-sp 2 C bonding state strongly contributed to the increase in the electrical conductivity. Nitrogen incorporation led to an increase in the sp 3 C-C bonding fraction in the films; as a result, the conductivity of the a-CN x films was found to be lower than that of the a-C films deposited under the same conditions.

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Photo-induced deformation of amorphous carbon nitride (a-CNx) thin films was observed under visible light irradiation. This phenomenon shows the energy conversion of photon energy to mechanical energy. The a-CNx films were prepared on rectangular ultrathin SiO2 substrates by reactive radio frequency magnetron sputtering method at different deposition temperatures. The graphite like films were obtained with increasing the deposition temperature. In order to evaluate the photomechanical response of a-CNx, the time resolved bending deformation of the a-CNx/SiO2 specimens was measured using optical-lever technique when the incident light was turned on and off. The absolute amount of bending deformation was found to be the maximum value with the specimen deposited at 573 K. As a result of the time resolved measurement of the photomechanical response of the a-CNx/SiO2 specimens, all of the specimens began to be bent immediately when the light was turned on and off, and then the deformation reached to the saturation value after about 4 s. The photomechanical response speed increased with increasing the nitrogen concentration, and the graphite like specimen showed low photomechanical responsivity.