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Silver macro‐texture substrates fabricated by plasma selective etching for surface‐enhanced Raman scattering
Author(s) -
Liu Fanxin,
Ye Xuhong,
Tang Chaojun,
Ma Hongtao
Publication year - 2013
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4209
Subject(s) - substrate (aquarium) , raman scattering , materials science , electric field , etching (microfabrication) , raman spectroscopy , layer (electronics) , plasma , texture (cosmology) , plasmon , analytical chemistry (journal) , dielectric , plasma etching , nanotechnology , optoelectronics , chemical engineering , optics , chemistry , chromatography , oceanography , physics , image (mathematics) , quantum mechanics , artificial intelligence , engineering , computer science , geology
We have demonstrated a novel method to generate the nanostructured substrate that shows a large enhancement with a spatially uniform enhancement factor of approximately 10 6 in surface enhanced Raman scattering (SERS). The substrates are fabricated using plasma selective etching. First, the Al 2 O 3 –TiC template which contains mixed Al 2 O 3 and TiC grains with the diameters of ~400 nm is selected as a base plate. The Al 2 O 3 and TiC grains have different physical properties, such as hardness, which corresponds to different etching rate in a plasma gas. Then, the Al 2 O 3 –TiC substrate is selectively etched to generate a random macro‐texture (MT) with different depths using the plasma of mixed gas of Ar and C 2 H 4 . Third, the MT substrate is deposited with a silver film (Ag). We further demonstrate that by varying the thickness of Ag layer, the EF is different which is confirmed by the plasmonic localized electric fields calculations using finite difference time domain. Finally, we combine this novel Ag MT substrate with ultrathin dielectric film, and the prepared substrates are coated with a 10 Å ta‐C film. The 10 Å ta‐C film can protect the oxygen‐free Ag in air and prevent Ag ionizing in aqueous solutions. More importantly, the ultrathin ta‐C can release the strongest plasmonic electric field to the outside of ta‐C layer and get a higher electric field than the uncoated Ag substrate. We expect that this method has more potential applications in analytic assays using SERS technology. Copyright © 2012 John Wiley & Sons, Ltd.