Temperature-induced reflectivity changes and activation of hydrogen sensitive optically thin palladium films on silicon oxide

Abstract

The optical properties of several thin metal film palladium-silicon oxide structures are examined at room temperature before and after annealing to 200 degrees C and also at 90 degrees C-in all cases in the presence of hydrogen gas. Multicycling sample activation is shown to occur iii the presence of hydrogen at room temperature with an increase in reflectivity on exposure to hydrogen, in contrast to thicker 80 Angstrom films. The reflectivity change increases with increasing film thickness (1-10 Angstrom). The surface activation at room temperature, before and after annealing to 200 degrees C, is compared with the performance at 90 degrees C, where it is shown that heat treatment strongly influences the behavior of the metal film. (C) 1998 American Institute of Physics. [S0034-6748(98)03809-X].