Large‐Scale Plasmonic Hybrid Framework with Built‐In Nanohole Array as Multifunctional Optical Sensing Platforms

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 16; no. 11; pp. e1906459 - n/a
• Main Authors: Wang, Xuejing, Ma, Xuedan, Shi, Enzheng, Lu, Ping, Dou, Letian, Zhang, Xinghang, Wang, Haiyan
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.03.2020; Wiley Blackwell (John Wiley & Sons)
• Subjects: Arrays; Computer simulation; Coupling; Detection; Dielectric properties; Etching; Gold; modulated photoluminescence (PL); Nanocomposites; Nanotechnology; Optical properties; Perovskites; Photoluminescence; plasmonic nanoholes (NHs); refractive index (RI) sensing; Refractivity; Submerging; surface plasmons (SPs); titanium nitride (TiN); plasmonic nanoholes (NHs); titanium nitride (TiN); surface plasmons (SPs); modulated photoluminescence (PL); refractive index (RI) sensing
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201906459

Light coupling with patterned subwavelength hole arrays induces enhanced transmission supported by the strong surface plasmon mode. In this work, a nanostructured plasmonic framework with vertically built‐in nanohole arrays at deep‐subwavelength scale (6 nm) is demonstrated using a two‐step fabrication method. The nanohole arrays are formed first by the growth of a high‐quality two‐phase (i.e., Au–TiN) vertically aligned nanocomposite template, followed by selective wet‐etching of the metal (Au). Such a plasmonic nanohole film owns high epitaxial quality with large surface coverage and the structure can be tailored as either fully etched or half‐way etched nanoholes via careful control of the etching process. The chemically inert and plasmonic TiN plays a role in maintaining sharp hole boundary and preventing lattice distortion. Optical properties such as enhanced transmittance and anisotropic dielectric function in the visible regime are demonstrated. Numerical simulation suggests an extended surface plasmon mode and strong field enhancement at the hole edges. Two demonstrations, including the enhanced and modulated photoluminescence by surface coupling with 2D perovskite nanoplates and the refractive index sensing by infiltrating immersion liquids, suggest the great potential of such plasmonic nanohole array for reusable surface plasmon‐enhanced sensing applications. This work presents two‐step fabrication of a titanium nitride nanohole thin film. Sub‐10 nm nanoholes are produced with large surface coverage and epitaxial quality. Enhanced transmission and optical anisotropy are observed in the visible regime. Modulated photoluminescence by coupling with two‐dimensional perovskites and refractive index sensing by infiltrating liquids are demonstrated toward surface plasmon‐based sensing applications.