A study on the correlation between the dewetting temperature of Ag film and SERS intensity

Abstract

The thermally dewetted metal nano-islands have been actively investigated as cost-effective SERS-active substrates with a large area, good reproducibility and repeatability via simple fabrication process. However, the correlation between the dewetting temperature of metal film and SERS intensity hasn’t been systematically studied. In this work, taking Ag nano-islands (AgNIs) as an example, we reported a strategy to investigate the correlation between the dewetting temperature of metal film and SERS intensity. We described the morphology evolution of AgNIs on the SiO2 planar substrate in different temperatures and got the quantitative information in surface-limited diffusion process (SLDP) as a function of annealing temperature via classical mean-field nucleation theory. Those functions were further used in the simulation of electromagnetic field to obtain the correlation between the dewetting temperature of Ag film and theoretical analysis. In addition, Raman mapping was done on samples annealed at different temperatures, with R6G as an analyte, to accomplish the analysis of the correlation between the dewetting temperature of Ag film and SERS intensity, which is consistent with the theoretical analysis. For SLDP, we used the morphological characterization of five samples prepared by different annealing temperatures to successfully illustrate the change in SERS intensity with the temperature fluctuation, obtaining a small deviation between the experimental results and theoretic prediction.

Ag-AgO nanostructures on glass substrates by solid-state dewetting: From extended to localized surface plasmons

“…The fabrication of Ag nanostructures by thermal annealing of thin films has been reported in diverse works controlling parameters such as the annealing temperature, the annealing time, and the deposition amount, evaluating even the final SERS response. 19,20,23,24 In a previous work, we analyzed the morphological and optical transitions from continuous films to discrete nanostructures for the case of Au films treated thermally at different temperatures. 21 Here, we extend the study to Ag with the highest extinction cross section coefficient associated with the excitation of SPs and showing SERS enhancement factors of 10 5 .…”

Fast Hydrogenation and Dehydrogenation of Pt/Pd Bimetal Decorated over Nano-Structured Ag Islands Grown on Alumina Substrates

“…A thicker NPs deposition might not be enough to form a continuous film as atoms deposited from the vapor phase undergo a series of kinetic processes, including thermal accommodation onto the substrate, surface diffusion of the atoms on the surface, dimer formation to initiate formation and growth [34]. More deposited atoms may help to grow small islands, contact with each other, and then merge into larger, but still compact islands [35,36].…”

Plasmonic nanomaterial structuring for SERS enhancement

“…12,13 Pertaining to SERS performance, an electromagnetic effect has been remarkably noted as a vital principle contributing to dramatic Raman signal enhancement compared to its counterpart, the chemical effect. 14,15 This mechanism triggers substantial local electromagnetic eld enhancement around a roughened surface, typically tailored by noble metallic nanoparticles due to the excitation of localized surface plasmon resonance (LSPR). [16][17][18] To date, gold (Au)-based nanostructures are regarded as robust materials for SERS detection, attributed to their intense SPR effects, biocompatibility and high chemical and thermal stability.…”