Dissipating heat for the fabrication of Au-Au dimers by optical printing

GARGIULO, JULIAN; IANINA L. VIOLI; BRICK, THOMAS; CORTES, EMILIANO; CERROTA, SANTIAGO; CHVÁTAL, LUKÁS; HERRERA, FACUNDO C.; ALBELLA, PABLO; REQUEJO, FELIX G.; MAIER, STEFAN A.; FERNANDO STEFANI

Londres

Simposio; London Plasmonic Forum; 2017

Optical printing holds great potential to enable the use of the vast variety of colloidalnanoparticles (NPs) in nano- and micro- devices and circuits. It allows the direct assembly ofNPs, one by one, onto specific positions of solid surfaces with great flexibility of patterndesign and no need of previous surface patterning. However, for unknown reasons it was notpossible to print NPs closer to each other than 300 nm, limiting its application to thefabrication of patterns of well separated NPs. Here we show that the repulsion restricting theoptical printing of close by NPs arises from light absorption by the printed NPs andconsequent local heating. We perform experiments under conditions of varying heatdissipation and model the results considering optical, thermophoretic and thermo-osmoticforces. By optimizing heat dissipation, it is possible reduce the minimumseparation between NPs. Using a reduced graphene oxide layer onto a sapphire substrate, wedemonstrate for the first time the optical printing of Au-Au NP dimers. A clear pathway isestablished for the optical printing fabrication of complex nano structures and circuits basedon connected colloidal NPs.