Tunable surface plasmonic property of Au/Au hybrid bullseye nanostructure

Metallic bullseye nanostructures have been widely studied for its enhanced focusing property for electric-field and surface plasmon (SP) excitations. Possible applications include plasmonic lenses, biological sensors, and light-absorption enhancement for solar energy devices. Focused ion beam (FIB), which is widely used as a single-step patterning technique, has been introduced to fabricate bullseye resonators with periodic concentric rings and grooves. We are showing a bullseye nanoresonator fabricated by FIB patterning with tunable plasmonic properties by employing Au/Ag hybrid metallic layers. The use of hybrid metallic structure, consisting of 50 nm Au on the top of 50 nm Ag can increase the sample quality, since Ag bullseye plasmonic lens has an intense surface plasmon resonance and appropriate plasmonic activity, and Au has a good chemical and structural stability. Tunable SP property can be found by using cathodoluminescence (CL) as the characterization technique. The strong background can be seen based on the fabrication method, however, we can investigate the tunable SP signal by controlling the excitation location, size, and the number of grooves.