Large‐Area Hybrid Plasmonic Optical Cavity (HPOC) Substrates for Surface‐Enhanced Raman Spectroscopy

Abstract

Surface-enhanced Raman spectroscopy (SERS) is receiving increasing interests owing to its high sensitivity and molecular fingerprint information. The practical application of SERS relies on the highly enhancing, uniform, reproducible, and affordable substrates. A novel gap-free 3D SERS substrate with unique hybrid plasmonic and optical cavity (HPOC) structures to improve the uniformity and reduce the fabrication cost while maintaining the high SERS enhancement is introduced here. The gold HPOC structures are fabricated by the tunable holographic lithography followed by gold deposition and can be conveniently optimized for a specific excitation wavelength by tuning the cavity length. The substrate shows average enhancement factor larger than 10 6 and excellent uniformity with a standard deviation smaller than 6.7%. Together with the capability to be fabricated on a flexible polyethylene substrate, the HPOC SERS substrate is promising for practical applications.

Engineering State‐of‐the‐Art Plasmonic Nanomaterials for SERS‐Based Clinical Liquid Biopsy Applications

“…An etching process was then performed to create ultrasmall nanopores of sub 10 nm in diameter on 2D silver nanoparticle supercrystals. [74] Sci.…”

Breaking the symmetry of nanosphere lithography with anisotropic plasma etching induced by temperature gradients

“…In addition, we show that the PS mushrooms produced can be used as a nanostructured template to easily produce various demanded plasmonic nanostructures, such as Au-capped nano mushroom arrays and ultra-small nanoapertures. [61][62][63][64] Although we have concentrated our attention on colloidal masks of PS spheres, PE-TG can be potentially explored for the etching of other polymeric particles, or even core-shell particles with a polymeric shell allowing you, with a pre-etch of the polymer shell, to alter the interparticle distances 65 , and in prospective overcome similar barriers encountered in other lithographic methods, for example optical mask lithographies, where creating patterns with an undercut is still challenging. 66,67 Fabrication aspects aside, we investigate the optical properties of the Au-capped nano mushroom arrays and their effectiveness as SERS substrate for biosensing applications.…”

Large‐Area Plasmonic Metamaterial with Thickness‐Dependent Absorption

“…[23,24] Holographic lithography (HL), on the other hand, can be used to prepare large area, highly uniform, and defect-free periodic structures with subwavelength feature size (<1 µm) by parallel exposure. [25,26] Conventional HL strategy relies on the distribution and number of the grating elements to change the length (width) and morphology of the top metal structures and therefore tune the absorption properties of plasmonic metamaterials. It requires elaborate structure designs and tedious fabrication process.…”