Silicon-coated plasmonic sensor with enhanced sensitivity for the detection of glucose solution

Abstract

A plasmonic refractive index sensor with nano-coating enhanced is numerically studied by finite element method. The sensor structure is composed of a metal-insulator-metal waveguide with baffle and a square frame with a gap cavity. The uncoated structure achieves a sensitivity of 1620.61 nm/RIU by optimizing gap width of the cavity. The investigation on the transmission spectra of various silicide-coated structures revealed that the structure with 15 nm silicon-coated achieves a sensitivity of 2079.45 nm/RIU, which is 28.31 % higher than that of the uncoated structure. Moreover, detection of glucose solution concentration using the silicon-coated structure achieved a sensitivity of 3.565 nm/%. These findings provide insights for the detection of highly sensitive plasmonic sensor.