Sensing properties for a microhydrogen sensor with modified palladium film

A microhydrogen gas sensor platform was fabricated by a MEMS process. A nano-bumpy structure was produced using a polystyrene aqueous suspension to develop the surface areas of the sensing area (palladium thin film). The palladium film was deposited on a fabricated platform by a radio frequency magnetron sputtering. A cross section of each AFM image was analyzed to determine the mean surface roughness. The root-mean square roughness of the 1-layer nano-bumpy Pd structure and 2-layers nano-bumpy Pd structure were 9.07 nm and 13.1 nm, respectively, whereas that of the Pd thin film was 0.98 nm. The sensitivities of the Pd thin film sensor, mono-layer nano-bumpy sensor and double-layers nano-bumpy sensor at hydrogen gas concentrations of 2000 ppm was 0.638%, 1.045% and 1.511%, respectively.