Wafer-Scale LSPR Substrate: Oblique Deposition of Gold on a Patterned Sapphire Substrate

Abstract

Label-free detection of biomolecules using localized surface plasmon resonance (LSPR) substrates is a highly attractive method for point-of-care (POC) testing. One of the remaining challenges to developing LSPR-based POC devices is to fabricate the LSPR substrates with large-scale, reproducible, and high-throughput. Herein, a fabrication strategy for wafer-scale LSPR substrates is demonstrated using reproducible, high-throughput techniques, such as nanoimprint lithography, wet-etching, and thin film deposition. A transparent sapphire wafer, on which SiO2-nanodot hard masks were formed via nanoimprint lithography, was anisotropically etched by a mixed solution of H2SO4 and H3PO4, resulting in a patterned sapphire substrate (PSS). An LSPR substrate was finally fabricated by oblique deposition of Au onto the PSS, which was then applied to label-free detection of the binding events of biomolecules. To the best of our knowledge, this paper is the first report on the application of the PSS used as an LSPR template by obliquely depositing a metal.

GLAD Based Advanced Nanostructures for Diversified Biosensing Applications: Recent Progress

“…These GLAD-fabricated nanostructures have recently been employed in various biosensing detection settings. Recently, Kim et al reported OAD-based LSPR substrates with a very high throughput by fabricating Au nanostructures (at 45°) over patterned sapphire substrates (PSS) [ 68 ] ( Figure 2 f). Very high LSPR sensitivity was obtained for various biomolecules and bioanalytes.…”

“… Different GLAD-structured thin films. ( a ) Slanted-post films; ( b ) zig-zag (chevron) films with 4 arms; ( c ) AgNR/SiO 2 SCL/SiO 2 /PCL/Ag multilayer substrates; ( d ) helical film; ( e ) vertical post structure (reproduced with permission from [ 67 ]); ( f ) 45° tilted top view of Au mushrooms (reproduced with permission from [ 68 ]). …”

LSP-SPP Coupling Structure Based on Three-Dimensional Patterned Sapphire Substrate for Surface Enhanced Raman Scattering Sensing

“…In various studies, it has been suggested that photon scattering is increased when using patterned sapphire substrate (PSS), resulting in enhanced light extraction [26]. Kim et al utilized wafer-level LSPR substrates by depositing Au films on patterned sapphire substrates and employed the prepared substrates for detecting biomolecules by observing LSPR shifts [27]. However, for 3D substrates such as PSS, a single metal film or particle cannot provide higher Raman enhancement.…”

Plasmonic Sensors: A New Frontier in Nanotechnology

“…In developing LSPR-based POC devices, a key challenge is to produce large-scale LSPR substrates that are reproducible and have high throughput. In a study included in this Special Issue, Kim et al fabricated wafer-scale LSPR substrates using reproducible high-throughput techniques such as nanoimprint lithography, wet etching, and the glancing angle deposition (GLAD) technique [ 28 ]. First, they fabricated hard masks of SiO 2 nanodots on a transparent sapphire wafer using nanoimprint lithography, which was anisotropically etched with a solution of H 2 SO 4 and H 3 PO 4 , resulting in a patterned sapphire substrate (PSS).…”