In 2014, Dr. Zhibing Zhan reported the fabrication of ordered and uniform Ag nanoparticles and their surface modification for to enhance the Performance of Surface Plasmon Resonance for Application in Solar Energy Conversion. The fabrication processes are shown in Fig. 1. UTAMs with the thickness of ~300 nm were carefully mounted on ITO coated Glass substrates. Using these UTAMs as patterning masks, Ag nanoparticles were fabricated on ITO (indium tin oxide)-coated glass by electron beam evaporation. After removing the UTAM by a scotch tape, a uniform TiO₂ shell layer was coated on the Ag nanoparticles by ALD to form Ag@TiO₂ core–shell nanocapsule structures. By accurately controlling the dielectric TiO₂ shells coated on ordered plasmonic Ag nanoparticle arrays, dipole and quadrupole SPR modes can be manipulated to coincide with each other. This finding offers a novel perspective to enhance the performance of SPR, which has important significance for its applications.

Fig. 1 Fabrication processes for ordered and uniform Ag@TiO₂ core–shell nanocapsule structures.

Reference: 

(5) Highly reproducible and sensitive SERS substrates with Ag inter-nanoparticle gaps of 5 nm fabricated by ultrathin aluminum mask (UTAM) technique
Q Fu, Z Zhan, J Dou, X Zheng, R Xu, M Wu, Y Lei
ACS applied materials & interfaces, 2015, 7 (24), 13322-13328