Scanning electron micrographs of (a) a submicron Al grating made with NIL, (b) gold nanoparticles fabricated from a BCP-fabricated NIL mold, (c) gold nanoparticles deposited on Si substrate with 0.1 M HF solution, and (d) gold nanoparticles fabricated by annealing a thin gold film. Insets show magnified images of the gold nanoparticles.
(Color online) Schematic illustration of a rotating turn-table tilted at 45° relative to the evaporation source to ensure that the metal is deposited only on the top of the PMMA resist layer and not in the bottom of the nanoimprinted holes.
(Color online) SERS response of R6 G drop cast on silicon, DBCP-NIL Au nanoparticle islands, drop-cast gold colloid, and annealed gold thin-film. The nanoparticle islands fabricated from the DBCP-NIL template generated the most significant effect on the charge-transfer component of the SERS enhancement mechanism due to near-field interactions at the 10 nm inter-particle separation region.
(Color online) Schematic illustrations showing the SPR grating covered with (a) water and (b) gold colloid solution. The grating is a two dimensional array of circular holes (500 nm pitch and 150 nm diameter holes) in Al, and the gold nanoparticles are 20.4 nm in diameter.
(Color online) Reflectivity of Au colloid solution on unpatterned Al, Al subwavelength grating covered with water, and Al submicron grating covered with gold colloid solution. All reflectivity spectra were referenced to the reflectivity of water on unpatterned Al to account for Fabry–Perot resonance and the optical absorption of water. Mie theory was used to calculate the spectrum of mono-disperse 20 nm-diameter Au colloid. SP theory was used to show the [1,0] and [1,1] grating modes for the Al grating, as indicated by the dotted vertical arrows.
Peak-height ratios of the rhodamine 6G SERS intensities at 614 and 773 cm− 1 with respect to the 1513 cm−1 peak.
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