Optical Response Properties of Stable and Controllable Au NanOrod Monolayer Meta-Arrays

摘要

Ordered assemblies of individual metal nanoparticle building blocks have been important platforms in exploring plasmon-based light-matter interactions. Despite the fact that such assemblies have been extensively constructed, the systemic investigations of their optical response properties are lacking. In addition, the poor structural stability of these assembled metastructures treated with organic or inorganic solvents is another issue. Here, we develop a facile and robust approach for constructing structurally stable and controllable Au nanorod monolayer meta arrays (NRMMAs) vertically aligned on a silicon substrate, via evaporation-induced self-assembly and electron beam exposure. By precisely controlling zeta-potential on the surface of Au nanorods (NRs) and the Debye length of the colloidal dispersion, we demonstrate a good manipulation of the edge-to-edge gap distance between the NRs, which agrees well with our theoretical predictions. Based on this precise control, far- and near-field optical responses of the Au NRMMAs are systematically demonstrated. These controllable and stable vertically aligned Au NRMMAs with abundant, uniform, and tunable "hot spots" provide useful optical material for practical applications.