Skip to Main Content
Your organization might have access to this article on the publisher's site. To check, click on this link:http://dx.doi.org/+10.1116/1.4767274
In this paper, the authors report on the fabrication, theory simulation, and optical characterization of X-shaped nanoscale plasmonic crystals (PCs) and their application in biosensors. X-shaped PCs with 30 nm feature line-widths and different intersection angles were fabricated by a combination of electron beam lithography and argon ion beam milling techniques. Both experimental measurement and finite-difference time-domain simulations were employed to study the transmission properties of PCs under two different incident light polarizations. With the reduction of the symmetry of the X-shaped PCs, the transmission spectra of PCs show a new peak at ∼900 nm in the near-infrared region, and the optical experimental results were consistent with the simulated results. Plasmonic crystal-based biosensors were then prepared by self-assembly of octadecanethiol to the PCs followed by biotinylation and immobilization of streptavidin to the biosensor. The sensing properties of the PC-based biosensors with a 30° intersection angle, which is enhanced by a localized surface plasmon resonance with the asymmetry of the PC, are superior to those with a larger intersection angle in biosensor application. The robust fabrication technique and the strategy for enhancing the sensitivity of the biosensor endow X-shaped PCs with a great competitive advantage over other candidates.