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TiN Nanorods as Effective Substrate for Surface-Enhanced Raman Scattering
journal contribution
posted on 2019-11-21, 23:43 authored by Fengtong Zhao, Xiaotian Xue, Wangyang Fu, Yuehua Liu, Yunhan Ling, Zhengjun ZhangOwing to its well-known chemical stability, thermal stability,
and complementary metal-oxide-semiconductor process compatibility,
titanium nitride (TiN) has recently been demonstrated as an excellent
alternative plasmonic material for noble metals. However, the lack
of systematic studies on its electromagnetic enhancement mechanism
has placed an obstacle on the realization of localized surface plasmon
resonance (LSPR) using this unique TiN substrate for surface-enhanced
Raman scattering (SERS) applications. In this study, we prepared TiN
nanorods using scalable high-throughput oblique angle deposition technique
and optimized its SERS effect by improving the crystallinity via annealing.
Remarkably, we directly observed the LSPR of the TiN nanorods by near-field
optical image and revealed its corresponding LSPR mode using finite
element analysis. The two resonance peaks in both near and far field
exhibit a red shift when increasing the length of the TiN nanorods,
which can be ascribed to the increase of electron cloud oscillation
distance with the same electron mobility. Therefore, our systematical
investigations have clarified the critical influences of both the
crystallinity and the length on the LSPR of TiN nanorods, thus providing
urgently required guidance for TiN SERS substrate design, as well
as LSPR device development.