The influence of defects induced by electron or ion beam lithography in the pre-surface region of the substrate on optical properties of plasmonic nanoparticles is analyzed. It is demonstrated that electron hopping between the defect sites of closely located nanoparticles is probable. The effect of electron transport via defect states will cause an apparent electrical connectivity between the nanoparticles and can be observed in extinction measurements. It is shown that this type of connectivity is important for gap sizes smaller than ∼10 nm and can reduce the actual light field enhancement.
FDTD simulation scene: two nanoparticles separated by a nano-gap. The defects due to electron/ion lithography are present in the sub-surface region.
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