Plasmonic–Photonic Interference Coupling in Submicrometer Amorphous TiO2–Ag Nanoarchitectures

• Published in: Langmuir Vol. 33; no. 43; pp. 12398 - 12403
• Main Authors: Hyam, Rajeshkumar S, Jeon, Jihoon, Chae, Songhwa, Park, Yong Tae, Kim, Sung Jae, Lee, Byeongchan, Lee, Choongyeop, Choi, Dukhyun
• Format: Journal Article
• Language: English
• Published: American Chemical Society 31.10.2017
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.7b01080

In this study, we report the crystallinity effects of submicrometer titanium dioxide (TiO2) nanotube (TNT) incorporated with silver (Ag) nanoparticles (NPs) on surface-enhanced Raman scattering (SERS) sensitivity. Furthermore, we demonstrate the SERS behaviors dependent on the plasmonic–photonic interference coupling (P-PIC) in the TNT-AgNP nanoarchitectures. Amorphous TNTs (A-TNTs) are synthesized through a two-step anodization on titanium (Ti) substrate, and crystalline TNTs (C-TNTs) are then prepared by using thermal annealing process at 500 °C in air. After thermally evaporating 20 nm thick Ag on TNTs, we investigate SERS signals according to the crystallinity and P-PIC on our TNT-AgNP nanostructures. (A-TNTs)-AgNP substrates show dramatically enhanced SERS performance as compared to (C-TNTs)-AgNP substrates. We attribute the high enhancement on (A-TNTs)-AgNP substrates with electron confinement at the interface between A-TNTs and AgNPs as due to the high interfacial barrier resistance caused by band edge positions. Moreover, the TNT length variation in (A-TNTs)-AgNP nanostructures results in different constructive or destructive interference patterns, which in turn affects the P-PIC. Finally, we could understand the significant dependency of SERS intensity on P-PIC in (A-TNTs)-AgNP nanostructures. Our results thus might provide a suitable design for a myriad of applications of enhanced EM on plasmonic-integrated devices.