The scattering and accommodation of nanoparticles on a periodic structured surface: a molecular dynamics study

Identifying mechanisms that could influence the controlled deposition of nanoparticles has significant implications for self-assembly and the fabrication of thin films. Reported here are calculations on the dynamics of nanoparticles impacting on periodic surfaces similar to those encountered during deposition. Surface structure has been generated by introducing periodicity to the standard Lennard-Jones (3-9) surface scattering potential, such that steps or grooves have been created with dimensions comparable to impacting nanoparticles. This periodicity introduces patterns of behaviour that arise from a coupling mechanism between the components of force that operate on a particle when in collision with a structural feature, and particles in collision with a 100 nm high step can undergo displacement of several thousand nm across a surface. With the introduction of a dissipative component, the above patterns of behaviour become far more complex; but retain several of the basic characteristics identified for elastic collisions. A consequence of extended motion on a stepped surface is that the calculations show particles preferentially collect at the step edge of a structural feature; a process that is aided by the presence of a favourable potential energy interaction and an enhancement of the mechanism responsible for dissipating particle momentum.