Porous Metal Frameworks on Silicon Substrates

Abstract:

In this work, we describe the use of porous Si as a base material for the production of porous metal layers by a galvanic displacement reaction. We have applied this process for the production of porous Pt, Au, Ru and Pd layers. By adding HF to the reaction bath, we achieve a virtually complete displacement of Si by the metal. We have worked with porous Si samples of different morphologies, obtained on differently doped Si substrates, and studied the influence of the chemical nature of the metal precursor on the morphology of the porous metal layer produced. The samples were studied by SEM with EDS, BET analysis, and voltammetry. Porous metal layers comprising random agglomerates of spherical particles with diameters between 50 and 100 nm are usually obtained, while the original porous Si samples show arrays of straight pores. With Au, using its ethylenediamine complex, the original straight pore morphology could be preserved.