Block copolymer-templated fabrication of periodic nanowire arrays with alternating compositions

Patterned metallic nanostructures are useful for many applications such as photonics and catalysis. Alternating structures composed of two or more metals are particularly interesting, as they may give rise to novel surfaces with hybrid properties. However, creating such structures on the nanoscale requires the employment of sophisticated fabrication schemes, which usually involves a few steps and extensive use of lithography.

In this work, we demonstrate a simple self-assembly approach for the creation of alternating wires of two metallic structures, which relies on microphase separated films of block copolymers as templates. Our approach harnesses the chemical distinction between the domains to selectively adsorb the metal precursors, and employs different conditions to control the penetration depth of the precursors in order to distinguish between metallized domains based on their spatial location in the film. A single plasma treatment step simultaneously converts the metal precursors in the differently metallized domains into metallic nanowires, which inherit the periodic structure and the alternating order from the film. This modular approach also allows for selective deposition of gold nanoparticles on the block copolymer film prior to the process, which results in alternating bare and decorated nanowires.