Interfacial Bonding Behavior between Silver Nanoparticles and Gold Substrate Using Molecular Dynamics Simulation

Molecular dynamics (MD) simulation was applied to the sintering behavior of silver nanoparticles on a gold substrate in order to elucidate the sintering mechanism of the nanoparticles on the substrate. The simulation revealed that silver atoms from 1 and 2 nm nanoparticles migrated freely because of their larger surface energy and then epitaxially reoriented to the gold substrate so as to reduce grain boundary energy. The silver nanoparticles were more spread out on the (011) gold substrate than on the (001) substrate, indicating that substrates with larger surface energy induce greater spreading rates. Consideration of the competition of neck growth and epitaxial growth in sintering of nanoparticles revealed that reduction of surface energy is the predominant driving force in the initiation of sintering of silver nanoparticles, and that the reduction of grain boundary energy is subsequently consequential.