Effect of magnesium oxide adhesion layer on resonance behavior of plasmonic nanostructures

The magnesium oxide (MgO) adhesion layer is proposed to avoid adverse effects of lossy metallic adhesion layers in thin film plasmonic nanostructures. Such adverse effects can be in the form of resonance broadening and a decrease in the resonance magnitude. We fabricate and test the quality of MgO adhesion layers and determine its optical properties through ellipsometry measurements. We also provide the plasmonic response of various plasmonic nanostructures (nanohole array, nanodisk array, dimer nanohole array, and bowtie slot antenna array) with a MgO adhesion layer and conventional adhesion layers including titanium (Ti), chromium (Cr), tantalum (Ta), and indium tin oxide (ITO). Our results show that unlike conventional adhesives, MgO has almost no adverse effect on the plasmonic resonance of the designed nanostructures.