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

A Pd/TiO₂/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 PH₃ -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 C₂H₅OH, C₂H₄, and NH₃ 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.