Use of thermal energy for surface contact potential gas detection

Abstract
In a recent paper, Christofides and Mandelis [J. Appl. Phys. 66, 3975 (1989)] postulated the existence of a hydrogen-induced modulation of the pyroelectric coefficient of polyvinylidene difluoride when a Pd film is exposed to hydrogen gas. Their evidence was a photothermally induced signal. By examining the theory of the hydrogen effect on Pd, we established that a more likely cause is the thermal modulation of the contact potential difference between the PD and the counter-electrode. We demonstrate that the same behavior is observed when hydrogen gas is exposed to a Pd-mica-Au capacitor as observed by Christofides and Mandelis.