Enhanced Stability in Surface Plasmon Resonance Sensor Using Prism Coupler Based on Au/Bi2O3 Bilayer Film

摘要

Surface Plasmon Resonance (SPR) sensing has become a comprehensive utilized technology for detection, measurement and analysis in a wide spectrum of fields, ranging from biotechnology, environmental monitoring to food and drug monitoring. In this study, Au/Bi_2O_3 bilayer films with various layer thicknesses were deposited by thermal evaporation method on BK7 prism substrates and then post-annealing was conducted under ambient conditions. The adhesive strength of Au/Bi_2O_3 and Bi_2O_3/prism was measured with different layer thicknesses. Also, the SPR responses (reflectance vs. incident angle) were investigated as a function of the thickness of Bi_2O_3 layer in the Kretschmann geometry using ethanol as dielectric. The results indicate that the adhesive strength between Au and prism was improved more than 3 times by introducing the Bi_2O_3 as buffer layer. And the SPR dips also demonstrate that SPR sensor based on Au/Bi_2O_3 bilayer films is practical, although the height of SPR dip with about 6nm Bi_2O_3 is approximately 4 times weaker than that of monolayer Au and the width (defined as FWHM) broadens from 9° to 11°.