Bi-analyte demonstration of non-resonant, single-molecule SERS with isolated lithographic enhancement structures (opens in new tab)

Single molecule Raman spectroscopy using isolated, circular ~ 110 nm diameter, multilayer insulator-metal-insulator-metal (MIM+) disk enhancement structures fabricated with 355 nm interferometric lithography in a 2D 400 nm period array is reported. Adenine and cytosine are selected as a bi-analyte pair, with comparable strength Raman lines arising from ring breathing modes in close proximity (A: 743 cm-1 shift and C: 807 cm-1 shift). Samples are soaked in 1:2 A:C mixtures diluted in water to ...