Formation of Spherical Nanoparticle Arrays Via Electron-Beam Lithography Using Electroless Gold Plating

Ordered arrays of metallic nanoparticles (NPs) are being developed for applications ranging from waveguides, nano-antennae, and optical switches to enhanced fluorescence sensors, surface enhanced Raman spectroscopy (SERS), and biosensors enhanced electromagnetic response. Recent theoretical analyses show that for arrays of spherical gold (Au) NP, the electromagnetic field enhancement can be up to 107 relative to an isolated NP. Current fabrication methods, such as nanosphere lithograhpy (NSL), focused ion beam (FIB) milling, and electron beam lithography (EBL) rely on thermal evaporation or sputtering to form the metallic NPs. The directional nature of this approach limits particle shapes that can be created. We have created gold nanoparticle arrays using electroless Au plating and successfully transformed the produced cylinders into spheroid particles.