Self-assembled synthesis of SERS-active silver dendrites and photoluminescence properties of a thin porous silicon layer

Via electroless metal deposition, well-defined silver dendrites and thin porous silicon (por-Si) layers are simultaneously prepared in ammonia fluoride solution containing AgNO3 at 50 °C. A self-assembled localized microscopic electrochemical cell model and a diffusion-limited aggregation mode are used to explain the growth of silver dendrites. The formation of silver dendritic nanostructures derives from the continuous aggregation growth of small particles on a layer of silver nanoparticles or nanoclusters (Volmer-Weber layer). Thin and homogeneous nanostructure por-Si layers display visible light-emission properties at room temperature. The investigation of the surface-enhanced Raman scattering (SERS) reveals that the film of silver dendrites on por-Si is an excellent substrate with significant enhancement effect.