The silver-coated silicon nano-particles were prepared by thermal decomposition, assisted with post-treatments of electrochemical polishing. Structure and morphology identification indicated the differences between Ag-coated p-type and n-type porous silicon layers were due to their different porosity, and the higher porosity of p-type porous silicon layers was suitable to form the cubic silver particles with nm size. The post-process was used to remove the excess Ag and Ag–O continents from the surface, and the processes were monitored by electric measurement and Raman scattering spectroscopy. The overall change in resistance and Raman spectra revealed the formation of silver-coated silicon nano-particles for p-type porous silicon layer.