Fabrication and investigation of PVD-Deposited gold SPR chips: A comparative study with a commercial chip

Abstract

rapid detection of extremely small variations in the refractive index of the surrounding medium. The performance of these sensors is strongly governed by quality, thickness and uniformity of chips used in the instrument. This study focuses on the fabrication of SPR chips through a simple, cost-effective, and reproducible approach based on the deposition of Cr/Au bilayers on a glass substrate using a resistive thermal evaporation technique. Cross-sectional FE-SEM, ellipsometry, optical spectroscopy, and AFM analyses were used to examine optical and structural characteristics of the chips, determining the thickness and assessing surface uniformity. The sensing performance was evaluated by monitoring shifts of the resonance angle in the reflection spectra of glucose solution with concentrations of 0.1, 0.25, 0.5, 1, 2.5, and 5% using the Autolab ESPRIT device. All measurements were carried out with both commercial and fabricated chips, and the results were compared to each other. The results showed that the fabricated chips with parameters such as average sensitivity of 84 degree/RIU and FWHM of 2547 millidegrees are as effective as commercial chips and could be used for in-house instruments.