Fabrication of single-crystal silicon micro pillars on copper foils by nanosecond pulsed laser irradiation

A nanosecond pulsed Nd:YAG laser was used to irradiate a mixture of silicon powders, polyimide and carbon black deposited onto a copper foil. Silicon micro pillars with a single-crystalline structure were successfully created through laser-induced material self-organization. The shape, orientation and growth rate of the pillars were controllable by varying the fluence, incident angle and scan speed of the laser. The resulting pillar-on-foil structures were applied as negative electrodes of lithium ion batteries, and excellent electrical capacities as well as charge/discharge cycle characteristics could be obtained. The applicability of the proposed method to the manufacture of three-dimensional microstructures was demonstrated.