Nanosphere Lithography: Synthesis and Application of Nanoparticles with Inherently Anisotropic Structures and Surface Chemistry

Early work with size-tunable periodic particle arrays (PPAs) fabricated by nanosphere lithography (NSL) demonstrated that the localized surface plasmon resonance (LSPR) could be tuned throughout the visible region of the spectrum. The LSPR is sensitive to changes in nanoparticle aspect ratio and local dielectric environment. This property has recently been exploited to develop a novel method of measuring surface-enhanced Raman scattering (SERS) excitation profiles. Single layer PPAs consist of size-tunable anisotropic nanoparticles that can be modified to exhibit anisotropic surface chemistry. This work demonstrates multiple schemes for PPA modification using self-assembled monolayers and colloid decoration. Nanoparticle anisotropy can be further exploited with the recent combination of NSL and reactive ion etching (RIE); this extends the two-dimensional PPA structure into the third dimension