The diffusion of Ag atoms into solid thin films was studied. It was found that the diffusion process was significant at temperatures just above ambient, and the associated activation energy was 2.5eV. Conductivity measurements indicated that Ag atoms formed an impurity band in the solid, with an activation energy of 0.26eV.

D.Sarkar, N.J.Halas: Applied Physics Letters, 1993, 63[17], 2438-40