Pulsed laser dewetting of patterned thin metal films: A means of directed assembly

Thin nickel films were patterned into various shapes and treated with a series of laser pulses. The edges and vertices of the patterned shapes act as programable instabilities, which enable directed assembly via dewetting when the laser energy density is above the melting threshold. The pattern formations were monitored as a function of laser pulse and the retraction process was attributed liquid dewetting and a subsequent resolidification. The calculated retraction velocity (83 m/s) and liquid lifetime (12.3 ns) were consistent with the measured nickel retraction distances. The vertices of the shapes had an initially larger retraction velocity which was attributed to an additional in-plane curvature. (C) 2008 American Institute of Physics.