The $\hbox{Pd/TiO}_{2}$/ $\hbox{n}$-LTPS Thin-Film Schottky Diode on Glass Substrate for Hydrogen Sensing Applications

A Pd/TiO
₂
/n-type low-temperature-polysilicon (n-LTPS) MOS thin-film Schottky diode fabricated on a glass substrate for hydrogen sensing is reported. The n-LTPS is an excimer-laser-annealed and PH
₃
-gas-plasma-treated amorphous-silicon (a-Si) thin film. At room temperature and -2-V bias, the developed MOS Schottky diode exhibited a high signal ratio of 1540 to 50 ppm of hydrogen gas, with a fast response time of 40 s, respectively. The signal ratio is better or comparable with that of other reported MOS-type hydrogen gas sensors prepared on Si or III-V compound substrate. In addition, the signal ratio is 7.6, 14, and 30 times over other interfering gases of C
₂
H
₅
OH, C
₂
H
₄
, and NH
₃
at room temperature and a concentration of 8000 ppm at -2-V bias, respectively. Thus, the developed MOS Schottky diode shows promise for the future development and commercialization of a low-cost hydrogen sensor.