Abstract:

We investigated physicochemical and electrical properties of a Pd-deposited WO₃ thin film based hydrogen gas sensor with Pd thickness, annealing temperature and operating temperature as variables. Experimental results show that WO₃ exhibits tetragonal polycrystalline  at 500 ℃. The addition of Pd suppresses grain growth of WO₃. Pd is an isolated small spherical grain on WO₃ thin film at 500 ℃. It agglomerates an irregular large grain or diffuses into WO₃ at 600 ℃. A 2 nm Pd-deposited WO₃ thin film shows good response and recovery property at 250 ℃.

Key words: gas sensor, semiconductor thin film, Pd catalyst