Application of Electric Bias to Enhance the Sensitivity of Graphene-Based Surface Plasmon Resonance Sensors

Abstract

Surface plasmon resonance sensors that incorporate graphene as one of the layers in the sensor structure have been proven to provide higher sensitivity in the detection of biomolecules, compared to sensors without graphene. Graphene an allotrope of carbon facilitates better adsorption to biomolecule samples due to the carbon-hydrocarbon affinity to biomolecules, thereby resulting in higher sensitive biosensors. Recently, a revolutionary method has been presented, at least in theory for now, that there is still a possibility to increase the sensitivity of the SPR sensors by the application of electric bias across the metal-graphene sensor system. A mathematical treatment to understand the physics of how the electrical bias contributes to an increase in sensitivity is presented in this chapter, using a sensor surface structure comprising of Au-MoS2-Gr. The results indicate that the application of electrical bias across the sensor surface consisting of Gr and other materials provides a method to increase the sensitivity of these biosensors. The scope and impact of this research can be felt in many industries that need sensors either in the food industry for food contamination check, harmful gas detection for environmental monitoring or safety measures, medical diagnostics etc.

A Voltage-Tuned Terahertz Absorber Based on MoS2/Graphene Nanoribbon Structure

“…The best way to solve for the conductivity of graphene is using the Kubo formalism, which accounts for both interband and intraband transitions. The optical conductivity of graphene is represented by Equations ( 1)-(3) [41,42]. The unique band structure of graphene leads to the excitation of specific surface plasmons when they are subjected to electromagnetic waves, as compared to conventional 2D electron systems [39,40].…”

“…The best way to solve for the conductivity of graphene is using the Kubo formalism, which accounts for both interband and intraband transitions. The optical conductivity of graphene is represented by Equations ( 1)-(3) [41,42].…”

Tunable High-Sensitivity Four-Frequency Refractive Index Sensor Based on Graphene Metamaterial

“…The conductivity of graphene is divided into two components, intraband conductivity and interband conductivity , which can be expressed via Kubo equation as follows [ 34 , 35 ]: …”

“…where δ g is the conductivity of graphene, ω is the radian frequency, ε 0 is the vacuum dielectric constant, ∆ is the thickness of graphene, and the thickness of graphene is 1 nm. The conductivity of graphene is divided into two components, intraband conductivity σ intra and interband conductivity σ inter , which can be expressed via Kubo equation as follows [34,35]:…”