Amorphous Pb(Zr, Ti)O3 thin film hydrogen gas sensor

The capacitive Pd/lead zirconate titanate (PZT)/Pt devices have been fabricated with amorphous Pb(Zrx, Ti1−x)O3 (x=0, 30, 53, 65, 90) thin films deposited using the sol–gel spin-coating technology. The PZT films have been characterized by TGA, DTA, X-ray diffraction (XRD), dielectric and electrical properties, and gas sensitivity measurement. It has been shown that the amorphous PZT film can be operative as a hydrogen gas sensor material. The gas sensitivity of Pd/PZT/Pt devices has been systematically studied, and it has been observed that the sensitivity of the turn-on voltage shift in dc I–V curves is as large as 2.3 V at 1000 ppm hydrogen gas diluted in air. Among the PZT films with different Zr/Ti ratios, it has been investigated that the PZT film with Zr/Ti=30/70 has the lowest dielectric loss, lowest leakage current, and highest gas sensitivity to hydrogen.