Wide-Band Spectral Control of Au Nanoparticle Plasmon Resonances on a Thermally and Chemically Robust Sensing Platform

Abstract

Gold nanoparticles on Al 2 O 3 -coated gold films are presented as a chemically and thermally robust platform for molecular sensing. Single particle spectroscopy as a function of Al 2 O 3 coating thickness shows reproducible gold nanoparticle scattering spectra in the range from 690 to 610 nm as the Al 2 O 3 thickness increases from 0 to 3.4 nm. Numerical simulation of these structures indicates that surface-enhanced Raman spectroscopy enhancement factors in excess of 10 6 can be achieved. The stability of the Al 2 O 3 -coated structures under high-power laser irradiation was tested, revealing stable scattering spectra upon irradiation with 100 W/mm 2 at the particle resonance wavelength. The presented structure solves challenges with thermal stability, wavelength tuning range, and Raman background signal associated with previously attempted approaches.

Effect of surface roughness on substrate-tuned gold nanoparticle gap plasmon resonances

“…The laterally polarized dipole component which is responsible for the green scattering spot was not considered in this calculation due to its small contribution to the main resonance peak. 5,6,19,20 …”

“…These features are known to correspond to scatterers with a low-frequency (red) vertical scattering resonance and a high-frequency (green) predominantly lateral scattering component. 6 Figure 1(b) presents peak-normalized single particle scattering spectra from 21 gold nanoparticles on the gold film. Only particles separated from their nearest neighbor by several µm were selected, but otherwise their selection was made at random.…”

Film-coupled nanoparticles by atomic layer deposition: Comparison with organic spacing layers

“…Therefore, it is of interest to explore alternative spacer layer possibilities based on inorganic systems. 15 One robust method to the fabrication of thin inorganic spacer layers is atomic layer deposition (ALD) of oxides directly on metal films. ALD utilizes alternating cycles of self-limiting surface reactions to deposit angstromscale thin films in a layer-by-layer fashion.…”

Recent advances in surface plasmon resonance imaging: detection speed, sensitivity, and portability

“…As an example, Lumdee et al developed a robust sensing platform where the gold film was coated with a thin layer of Al 2 O 3 for both spectral tunability and protection. The sensor chip has demonstrated extreme stability under high-power laser irradiation of 100 W/mm 2 at resonance wavelength [71].…”