Multi-metallic Sensing Layers for Surface Plasmon Resonance Sensor

This article describes the analytical study of multi-metallic sensing layer of surface plasmon resonance (SPR) sensor. The monolayer gold, bimetallic silver-gold, trimetallic gold-silver-gold, and four-metallic layer silver-gold-silver-gold are characterized in this study. Furthermore, novel adhesive layer 3 nm of the aluminum film is proposed to replace the chromium. The four-layer of silver and gold around 40 nm in total thickness is proposed to enhance the quality factor of reflectivity dip, sensitivity, and the dynamic range of the sensing. The four-metallic sensing achieves the highest intrinsic sensitivity value of 27.6 RIU-1 and the detection range of refractive index value up to 1.407 RIU. This finding is potential for the sensor development for high refractive index solution.