Temperature dependent response/recovery characteristics of Pd/Ni thin film based hydrogen sensor

This paper demonstrates a new phenomenon that the response performance of Pd/Ni film in the heating mode improves a lot compared with room temperature. Based on the phenomenon, Pd/Ni thin film resistive hydrogen sensor integrated with heating resistance wire is fabricated to operate in the heating mode. Through the tests at different operating temperatures, we find that there exists an optimum temperature of 75 degrees C, when the operating temperature exceeds the optimum temperature, the sensing response drops accompanying with the increase of noise signal. At the optimum temperature, the response/recovery time are 7 s/6 s and the sensing response reaches 3.17% at 2% hydrogen. The sensitivity in the heating mode is twice as high as that at room temperature, and the non-linear error is half.