Sensitivity enhancement of a surface plasmon resonance based biomolecules sensor using graphene and silicon layers

A surface plasmon resonance based biomolecules sensor using silicon and graphene layers coated over the base of the high index prism sputtered with gold has been analyzed. The graphene layer has been used to enhance the adsorption of biomolecules while the addition of silicon layer between gold and graphene increases the sensitivity. The thicknesses of gold and silicon layers along with the number of graphene layers have been optimized to achieve the best performance of the sensor in terms of sensitivity and Full Width at Half Maximum (FWHM). To see the effect of wavelength of the light source, simulations have been carried out for three different wavelengths. The best performance is obtained for 633 nm wavelength with optimized thicknesses of gold and silicon layers as 40 nm and 7 nm respectively while the optimum number of graphene layers is 2. The sensitivity obtained with optimized parameters and additional silicon layer, is more than twice the value reported in the literature.