1:45 PM - 2:00 PM
▲ [23p-A101-4] 2D MoO3 Nanowires for Surface-Enhanced Raman Spectroscopy
Keywords:Molybdenum trioxides, Mie resonance, Surface-enhanced Raman scattering
Semiconductor-based surface-enhanced Raman scattering (SERS) substrates operated by charge transfer (CT) mechanism have received much attention in the recent years because they circumvent the drawbacks of localized plasmonic resonances (LSPRs) of metal-SERS substrates resulting in significant photo-thermal heat generation and poor reproducibility. However, the enhancement factor (EF) of semiconductor-based SERS substrates (EF value: 10^6) are substantially poorer than those of metal-based SERS (EF value: 10^10). The current enhancement strategies in semiconductors relying heavily on CT mechanism are less than other enhancement mechanisms relating to the electromagnetic mechanism (EM) at nano scale. In this presentation, we report the self-assembled α-MoO3 nanowires as 2D van der Waals material, which aims at fabricating high-performance EM-based semiconductors SERS-active substrates comparable to that of noble metals.
The systematic control of the fabrication conditions provided MoO3 nanowires with different morphologies when using pulsed laser deposition. We found that the nanowires showed strong light scattering at around 400-500 nm in the visible range by comparing the normal and diffused reflectance measurements. This optical behavior may be related to presence of a near-field on the nanowire surfaces and may be due to the Mie resonance related to correlation between a structure size and a wavelength of light. This optical resonance provides an increased near-field contributing to enhanced coupling of the incident light to the organic molecule (R6G), which results in the strong SERS effect of the nanowires. We are calculating using the FDTD analysis to elucidate presence of near-field on the nanowire surfaces. In addition, we are studying the strong SERS effect of the MoO3 nanowires from the viewpoint of defect engineering. Our substrates are expected to obtain a high EF value of 10^8 by both mechanisms of EM and CT models.
The systematic control of the fabrication conditions provided MoO3 nanowires with different morphologies when using pulsed laser deposition. We found that the nanowires showed strong light scattering at around 400-500 nm in the visible range by comparing the normal and diffused reflectance measurements. This optical behavior may be related to presence of a near-field on the nanowire surfaces and may be due to the Mie resonance related to correlation between a structure size and a wavelength of light. This optical resonance provides an increased near-field contributing to enhanced coupling of the incident light to the organic molecule (R6G), which results in the strong SERS effect of the nanowires. We are calculating using the FDTD analysis to elucidate presence of near-field on the nanowire surfaces. In addition, we are studying the strong SERS effect of the MoO3 nanowires from the viewpoint of defect engineering. Our substrates are expected to obtain a high EF value of 10^8 by both mechanisms of EM and CT models.