Silver nanometer-scale thin films by electroless deposition on insulating surfaces activated by gold nanoparticles

In this work, electroless deposition (ELD) of nanometer-scale silver (Ag) thin films on amino-terminated SiO₂ surfaces activated by gold nanoparticles (AuNPs) has been studied. Experimentally obtained results show that the saturated number of 5 nm AuNPs adsorbed on the surfaces is considerably higher than that of 15 nm and 25 nm ones. Moreover, they precipitate substantially faster relative to their larger counterparts. As a result, substrate activation by 5 nm AuNPs needed for subsequent metallization is ∼6 and ∼9 times faster than activation with Pd or 15 nm AuNPs, respectively. Successful deposition of high quality Ag thin films on such surfaces was revealed by HRSEM imaging. During film growth, three distinct stages were observed: compact and isolated islands, coalesce equilibrium shapes, and continuous hole-free deposits. The optical and electrical properties of the films have been investigated and demonstrated in this work.