Sputtering of nanoparticles: Molecular dynamics study of Au impact on 20 nm sized Au nanoparticles

Using molecular dynamics simulation we study the sputtering of Au nanoparticles (diameter 20 nm) by 16 and 64 keV Au projectiles. The sputter yield is more than a factor of two larger than for sputtering of a planar target. This feature is connected to a reduced projectile range in the nanoparticle, which leads to shallow energy deposition and pronounced spike sputtering. The sputter yield shows only little dependence on the impact parameter of the nanoparticle. Even at peripheral impacts at 9 nm from the nanoparticle centre, the sputter yield has decreased by only 20% compared to central impacts. Sputter emission accelerates the nanoparticle in the opposite direction to velocities of several m/s.