Self-organized gold nanostructures on laser patterned PET

Irradiation of polyethyleneterephtalate (PET) with linearly polarized light from a pulsed 248 nm KrF laser with 6000 pulses per area and fluences between 2.0 and 8.4 mJ·cm− 2 resulted in formation of coherent ripple patterns with a lateral periodicity in the order of laser light wavelength and structure depth of several 10 nm. The structure period could be controlled by variation of the incidence angle of the laser beam. Subsequently, thin gold layers were deposited onto the laser patterned PET surface either by sputtering and evaporation. The resulting structures were analyzed by atomic force microscopy (AFM) and focused ion beam cuts in combination with scanning electron microscopy (FIB-SEM). Evaporation leads to a continuous metal coverage copying the nanostructured polymer surface, while sputtering leads to formation of isolated nano-wires on the ridge of the laser-induced ripples. The width of the gold nano-wires could be tailored by the ripple periodicity formed before the deposition process.