Improving the Detection Accuracy of an Ag/Au Bimetallic Surface Plasmon Resonance Biosensor Based on Graphene
Qi Wang,
Shuhua Cao,
Xufeng Gao,
Xinrui Chen,
Dawei Zhang
Affiliations
Qi Wang
Shanghai Key Laboratory of Modern Optics System, Engineering Research Center of Optical Instrument and System, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Rd, Shanghai 200093, China
Shuhua Cao
Shanghai Key Laboratory of Modern Optics System, Engineering Research Center of Optical Instrument and System, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Rd, Shanghai 200093, China
Xufeng Gao
Shanghai Key Laboratory of Modern Optics System, Engineering Research Center of Optical Instrument and System, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Rd, Shanghai 200093, China
Xinrui Chen
Shanghai Key Laboratory of Modern Optics System, Engineering Research Center of Optical Instrument and System, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Rd, Shanghai 200093, China
Dawei Zhang
Shanghai Key Laboratory of Modern Optics System, Engineering Research Center of Optical Instrument and System, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Rd, Shanghai 200093, China
A theoretical study was conducted with the aim of improving the detection accuracy of graphene-based surface plasmon resonance (SPR) biosensors. We studied the effect of applying a bias voltage to the sensor surface on its detection accuracy. The optimum thicknesses of silver and gold layers in the biosensor of 47 nm and 3 nm, respectively, were determined. Graphene layers deposited on these thin silver and gold films formed a sensor surface system, on which the surface plasmons were excited. The real and imaginary parts of the refractive index of graphene were controlled by the bias voltage. When the chemical potential was increased from 36 meV to 8 eV, the detection accuracy of the sensor was correspondingly increased by 213%.
