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Surface‐enhanced Raman scattering sensing on black silicon
Author(s) -
Gervinskas Gediminas,
Seniutinas Gediminas,
Hartley Jennifer S.,
Kandasamy Sasikaran,
Stoddart Paul R.,
Fahim Narges F.,
Juodkazis Saulius
Publication year - 2013
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.201300035
Subject(s) - materials science , black silicon , rhodamine 6g , raman scattering , wafer , coating , silicon , optics , colloidal gold , optoelectronics , raman spectroscopy , specular reflection , drop (telecommunication) , reactive ion etching , substrate (aquarium) , etching (microfabrication) , analytical chemistry (journal) , nanoparticle , nanotechnology , oceanography , physics , geology , telecommunications , chemistry , chromatography , computer science , layer (electronics) , fluorescence
Reactive ion etching was used to fabricate black‐Si over the entire surface area of 4‐inch Si wafers. After 20 min of the plasma treatment, surface reflection well below 2% was achieved over the 300–1000 nm spectral range. The spikes of the black‐Si substrates were coated by gold, resulting in an island film for surface‐enhanced Raman scattering (SERS) sensing. A detection limit of 1 × 10 −6 M (at count rate > 10 2 s −1 . mW −1 ) was achieved for rhodamine 6G in aqueous solution when drop cast onto a ∼ 100‐nm‐thick Au coating. The sensitivity increases for thicker coatings. A mixed mobile‐on‐immobile platform for SERS sensing is introduced by using dog‐bone Au nanoparticles on the Au/black‐Si substrate. The SERS intensity shows a non‐linear dependence on the solid angle (numerical aperture of excitation/collection optics) for a thick gold coating that exhibits a 10 times higher enhancement. This shows promise for augmented sensitivity in SERS applications.