Structures and N2-sorption properties of carbonaceous films prepared by high-powered sputtering of d-phenylalanine

Amino acid-based carbonaceous films were prepared by the radio-frequency (rf) sputtering of d-phenylalanine under the rf power density from 0.18 to 0.53 W/cm2. As the rf power was increased, the deposition rate tended to increase, especially for 120-W sputtering. The surface of carbonaceous films prepared by high rf power have rugged surfaces following their storage in a vacuum box. The carbonization of the sputtered films progressed with rf power; the oxygen and nitrogen content in the films decreased as rf power increased, as well as the content of CH moieties decreased. Increasing the rf sputtering power enhanced the N2-sorption capability and the viscous character of the carbonaceous films. The quartz crystal resonators coated with the carbonaceous films by the highest rf sputtering power had superior resonance signals toward the N2 sorption-desorption measurement with suppressed noise.