Precise Capillary-Assisted Nanoparticle Assembly in Reusable Template

Capillary-assisted particle assembly (CAPA) in predefined topographical templates is a scalable method for the precise positioning of nanoscale objects on various surfaces. High-resolution CAPA templates are typically fabricated by expensive electron-beam lithography and are used for a single assembly process. To increase the scalability and reduce the costs of the CAPA technique, the fabrication and characterization of reusable templates with nanoscale funnel-shaped traps for repetitive precise nanoparticle placement are demonstrated. The yield of the first assembly of 100 nm gold nanoparticles (AuNPs) is as high as 94% with a median position offset of about 10 nm. The subsequent transfer process of the AuNPs from the silicon assembly template onto polymer surfaces, such as the elastic polydimethylsiloxane or the inelastic OrmoComp, shows a transfer yield larger than 99%. After the first transfer process, the assembly template is reused, resulting in a position offset and an assembly and transfer yield of this second assembly/transfer step that are comparable to the first ones. The obtained results demonstrate that the nanotemplates made by electron-beam lithography can be reused for repeatable CAPA processes and thereby eliminate the need for recurring lithography steps for each assembly and thus make the CAPA technique more cost-efficient.

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