Structural Characterization of Nanoparticle Arrays

Optical Properties of Electron Beam Lithography-Fabricated Nanoparticle 

In the case of square arrays of Au and Ag cylinders (D = 200 nm, h = 35 nm, and d= 250-500 nm), die extinction shifts 62 and 55 optical nm for a 100 nm change in nanoparticle lattice spacing for the Au and Ag arrays, respectively. Based on die linear regressions, die coupling effects appear to slightly more significant in the square arrays. 

This work has demonstrated that the LSPR of Au and Ag nanoparticle arrays exhibit pronounced blue shifts as lattice spaeing is decreased. The blue shifts were foimd to occur for both hexagonal and square lattices, with slight differences between lattices. These differences correlate with lattice density such that denser lattices give bluer X,, . In addition, the Au and Ag results are very similar, which demonstrates that these two metals have similar dielectric properties for LSPR in the far-red and near-infi red in spite of the fact that they have significant differences in behavior below 700 nm. 

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