Both the deposition of metal nanoparticles and direct laser writing of nanostructures onto silicon surfaces have been widely studied for applications such as catalysis and sensing. This presentation discusses how metal nanoparticle deposition and laser writing onto silicon can be combined in a single step using the technique of reactive laser ablation in liquid (RLAL). In RLAL, a silicon wafer immersed in aqueous solution containing one or more metal precursors such as Cu(NO3)2, KAuCl4, and AgNO3 is ablated with focused femtosecond laser pulses. Using this technique, cubic or spherical Cu nanoparticles with controlled size and particle density are deposited onto silicon laser-induced periodic surface structures (LIPSS). The deposition mechanisms are analogous to conventional electrodeposition of Cu onto silicon: hydrated electrons from the laser plasma nucleate Cu0 and the Cu nanoparticles grow through Volmer-Weber (island) mechanism. The RLAL technique also produces Au or Ag nanoparticles on silicon LIPSS when the Cu precursor is replaced by Au or Ag precursors. The deposition of Au and Ag nanoparticles onto silicon LIPSS is enhanced by at least 50% when Cu precursor is added to the Au or Ag-containing solution, suggesting that a galvanic replacement reaction of Cu by Au or Ag operates to enhance deposition of these metals onto the silicon LIPSS.

Deposition and growth of metal nanoparticles with controllable size and shape onto silicon laser-induced periodic surface structures

ACS Fall 2021

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