Pd-Al_2O_3-Alトンネルダイオード水素ガスセンサの表面汚染と水素応答

概要

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A Pd-Al_2O_3-Al tunnel diode acts as hydrogen gas sensor because hydrogen atoms adsorbed at the Pd-Al_2O_3 interface reduce the work function of Pd and in turn the barrier height between Al_2O_3 and Pd electrode, accordingly increasing the tunnel current of the device. Long term stability is very inlportant for this device to be used as a practical gas sensor. In this paper, we present experimental data on the change in hydrogen response time of the Pd tunnel diode sensor due to storage in air with and without 0.1% SO_2. The contaminants on the Pd surface which degrade the response time are revealed to be both O and S by Auger electron spectroscopy measurements. Oxygen aton1s adsorbed on the Pd surface can be removed when hydrogen is introduced, whereas su1fur continues to stay on the Pd surface resulting in a continual degradation of hydrogen sensitivity of the device.
山形大学の論文
2003-02-17