Transfer Printing of Nanoplasmonic Devices onto Flexible Polymer Substrates from a Rigid Stamp

Plasmonic colour filters and polarizers were fabricated using a nanotransfer printing technique, where aluminium nanostructures were directly transferred from a metal coated silicon stamp on to a piece of polycarbonate (PC) sheet. Using a moderate pressure of 10 bar and a temperature of 120 A degrees C, an area of 10 x 12 mm was successfully printed, with a minimum feature size of 75 nm. Slight undercutting of the silicon stamp structure helped to separate the top metal from that on the sidewalls and to greatly improve the printing quality. The metal film printed on to the PC substrate showed a smoother surface than those directly evaporated onto the silicon stamp. The plasmonic colour filters fabricated using this fast and inexpensive technique demonstrated similar functionalities to devices fabricated using electron beam lithography and dry etch processing. Experimental results for filters and wire grid polarizers were in good agreement with simulations.