Optically thin palladium films on silicon-based substrates and nanostructure formation: effects of hydrogen

Optically thin palladium films evaporated on different silicon-based substr ates are investigated following exposure to different concentrations of hyd rogen gas in air. Laser modulated reflectance off the palladium surface of silicon oxide, silicon nitrite and polycrystalline silicon substrates is us ed to recover information regarding changes in optical properties of the sa mples due to the absorption of hydrogen. Simple index of refraction argumen ts are sufficient to explain the results. Structural changes of the palladi um films have been investigated using atomic force microscopy before and af ter hydrogen exposure. An interesting nanostructure formation is evident in some of the samples, leading to a possible means of fabricating nanodevice s. (C) 2000 Elsevier Science B.V. All rights reserved.