Analytical modelling of monolayer graphene-based ion-sensitive FET to pH changes

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Graphene exhibits unique properties like high sensitivity and biocompatibility, making it ideal for pH sensing.
• Graphene-based ion-sensitive field-effect transistors (ISFETs) with ionic liquid gates are emerging as sensitive pH sensors.
• Enzyme stability and catalytic efficiency are critically dependent on precise pH control.

Purpose of the Study:

• To simulate and analyze the electrical characteristics of a monolayer graphene-based ISFET pH sensor.
• To develop an electrical detection model for graphene ISFETs across a range of pH values.
• To establish a relationship between hydrogen ion concentration and carrier concentration in graphene.

Main Methods:

• Simulating electrical measurements of a monolayer graphene-based ISFET with buffer solutions at varying pH.
• Developing a conductance model for monolayer graphene to establish an electrical detection model.
• Proposing a model relating hydrogen ion (H+) concentration to carrier concentration using a defined control parameter (Ƥ).

Main Results:

• An analytical model for the graphene ISFET pH sensor was developed.
• The model demonstrates good agreement with experimental data for different pH values.
• A relationship between H+ concentration and carrier concentration was established, influenced by surface ion absorption.

Conclusions:

• The monolayer graphene-based ISFET shows significant potential for accurate pH sensing.
• The proposed analytical model provides a reliable method for predicting sensor performance.
• Optimized graphene sensors can enhance the reliability and application scope of enzymes as catalysts.