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Owing 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.

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To enlarge the surface-enhanced Raman scattering (SERS) enhancement of Ag nanopillar arrays, a well-controlled armrest Ag NRs@Al2O3 structure was designed, aiming at triggering efficient resonance between the nanopillar and the Ag NRs. A series of armrest Ag NRs@Al2O3 with well-designed morphology as well as enhanced “hot spots” quantity by taking advantage of AAO template and oblique angle deposition were successfully fabricated. Both experimental results and numerical simulations revealed localized surface plasmon resonance (LSPR) tunability by simply optimizing the arm length. An optimal substrate with outstanding SERS performance for dyes and biomolecular was realized by enhancing the hot spots area while tuning the resonance peak close to the 785 nm excitation. The as-fabricated 14-Ag NRs@Al2O3 without any surface modification presented a glucose detection limit of 1 × 10–4 mM, endowing our SERS platform for sensitive label-free biodetection.

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