Nanopatterning by biological templating and laser direct writing in thin laser deposited films

Abstract

We report on three alternative approaches to laser-supported sub-micro- and nanopatterning of ultrathin films. The inherent non-linearities of direct writing techniques can be used to fabricate structures far below the optical resolution limit. Due to the non-linear dependence of light absorption and reaction rate on film thickness and temperature (a) the lateral self-limitation of the oxidation reaction in ultrathin titanium films on a transparent heat insulating substrate in air can occur. The polarization of sharp conducting tips results in (b) near-field enhancement of the optical field in nanometer regions that allows diminishing of the effective size of the radiation source. The third approach (c) is based on the nanometer-period pattern transfer from a biomolecular template to a Pt/C overlayer deposited by cross-beam pulsed laser deposition.