Large-area, well-ordered, uniform-sized bowtie nanoantenna arrays for surface enhanced Raman scattering substrate with ultra-sensitive detection

We report the fabrication of large-area, well-ordered, uniform-sized noble metal bowtie nanoantenna arrays used as an ultra-sensitive surface-enhanced Raman scattering (SERS) substrate by a refined combination of colloid lithography and subsequent oxygen plasma processing. The tip-to-tip distance between neighboring nanotriangles is made as small as 10 nm by accurately controlling the etching time. Owing to the nanoscale property, the as-fabricated Ag bowtie nanoantenna arrays exhibit a local SERS enhancement larger than 107. The experimental results were confirmed by theoretical calculations.