Obliquely Deposited Titanium Nitride Nanorod Arrays as Surface-Enhanced Raman Scattering Substrates.

Yi-Jun Jen,Hou-Lon Cheang,Meng-Jie Lin,Teh-Li Chan

doi:10.3390/s19214765

Yi-Jun Jen, Hou-Lon Cheang + Show 2 more

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https://doi.org/10.3390/s19214765

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Abstract

In this work, titanium nitride (TiN) nanorod arrays were prepared as surface-enhanced Raman scattering (SERS) substrates using glancing angle deposition (GLAD) in a magnetron sputtering system. The nitrogen flow rate was varied from RN2 = 1 to 3 sccm, yielding five TiN uniform thin films and five TiN nanorod arrays. The figure of merit (FOM) of each TiN uniform film was measured and compared with the SERS signal of each TiN nanorod array. Rhodamine 6G (R6G) was used as the analyte in SERS measurement. For an R6G concentration of 10−6 M, the analytical enhancement factor (AEF) of the TiN nanorod array that was prepared at RN2 = 1.5 sccm was 104. The time-durable SERS performance of TiN nanorod arrays was also investigated.

Highlights

Over the last several decades, surface plasmon resonance has been investigated to develop its optical and sensing applications [1,2]
The optical property of titanium nitride (TiN) thin films was analyzed by variable angle spectroscopic ellipsometry
The permittivity of the TiN thin films was obtained by fitting the spectroscopic elliptical parameters of the polarization state using the Drude−Lorentz model [30]

Summary

Introduction

Over the last several decades, surface plasmon resonance has been investigated to develop its optical and sensing applications [1,2]. When light is incident on metal nanostructures, the collective oscillation of free electrons around the nuclei in the subwavelength surface is called localized surface plasmon resonance (LSPR) [3]. SERS is a powerful, nondestructive tool for ultrasensitive vibrational spectroscopy. It has been applied in chemistry and biology, including the detection of chemical and biological agents, biomedical diagnostics, DNA analysis, and pH sensing [7,8]. Various metal nanostructures were developed to support the LSPR for SERS. Silver or gold nanoparticle arrays fabricated with a lithography technique have been proposed in SERS applications [9]. Tilt nanorod arrays [13,14] and nanohelix arrays [15] have been mass-produced in a typical physical vapor deposition system and applied as SERS substrates

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