Self– versus Directed– assembly of Nanoparticles via Pulsed Laser Induced Dewetting of Patterned Metal Films

A nanoscale, synthetic perturbation was all that was required to nudge a natural, self–assembly process toward significantly higher order. Nanolithography was used to impose the perturbation which ultimately led to an organized nanoparticle array. Specifically, liquid–phase pulsed laser induced dewetting (PLiD) was used to transform metallic thin film strips into nanoparticle arrays. Initially, thin film strips retracted into fluid rivulets. Rivulet breakup followed, forming linear nanoparticle arrays via a process resembling the Rayleigh-Plateau (RP) instability; nanoparticle diameter and pitch were poorly controlled and disperse. We then demonstrated that the assembly accuracy and precision could be drastically improved by merely imposing a synthetic sinusoidal perturbation onto the lateral surfaces of the thin film strip. The synthetic perturbations in the strip translated into an unstable varicose oscillation on the rivulet during retraction – a precise nanoparticle diameter and pitch emerged thereby superseding the otherwise naturally evolving modes predicted by the modified Rayleigh-Plateau instability.