Simultaneous palladium and silver deposition on porous silicon (PS) by immersion plating from aqueous [Pd(NH3)(4)](2+) and [Ag(NH3)(2)](+) complexes were carried out and studied by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis and X-ray diffraction. As the measurements revealed, the deposits were individual Pd and Ag seeds both in the pores and on the surface of the PS without forming Pd-Ag alloys. Palladium was present in the form of small spherical grains with diameter of 1-40 nm. In case of silver, two types of deposits could be distinguished. When high silvercomplex ion concentration was applied, the deposition of Ag grains (d = 60-100 nm) took place in the pores and on the surface as well. In case of lowered [Ag(NH3)(2)](+) concentrations, the formation of a three-dimensional porous silver networks (built up from silver particles of 30-40 nm in diameter)-on the top surface of the porous silicon layer-was advanced. (C) 2002 Elsevier Science B.V. All rights reserved.