Compact Modeling of Two-Dimensional Field-Effect Biosensors

• Published in: Sensors (Basel, Switzerland) Vol. 23; no. 4; p. 1840
• Main Authors: Pasadas, Francisco, El Grour, Tarek, G Marin, Enrique, Medina-Rull, Alberto, Toral-Lopez, Alejandro, Cuesta-Lopez, Juan, G Ruiz, Francisco, El Mir, Lassaad, Godoy, Andrés
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01-02-2023; MDPI
• Subjects: Antigens; biosensor; Biosensors; Carrier transport; Charge density; Chemical compounds; Chemical reactions; Circuit design; Design standards; Electrodes; Electrolytes; Electrostatics; field-effect transistor; Graphene; immunosensor; Internet of Things; Low dimensional semiconductors; Macromolecules; Medical equipment; Membranes; modeling; Modelling; MoS2; Permeability; Physiological apparatus; Sensors; Surface charge; Transistors; 2D; biosensor; modeling; two-dimensional; MoS2; immunosensor; TMD; sensor; field-effect transistor; Verilog-A
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s23041840

A compact model able to predict the electrical read-out of field-effect biosensors based on two-dimensional (2D) semiconductors is introduced. It comprises the analytical description of the electrostatics including the charge density in the 2D semiconductor, the site-binding modeling of the barrier oxide surface charge, and the Stern layer plus an ion-permeable membrane, all coupled with the carrier transport inside the biosensor and solved by making use of the Donnan potential inside the ion-permeable membrane formed by charged macromolecules. This electrostatics and transport description account for the main surface-related physical and chemical processes that impact the biosensor electrical performance, including the transport along the low-dimensional channel in the diffusive regime, electrolyte screening, and the impact of biological charges. The model is implemented in Verilog-A and can be employed on standard circuit design tools. The theoretical predictions obtained with the model are validated against measurements of a MoS
field-effect biosensor for streptavidin detection showing excellent agreement in all operation regimes and leading the way for the circuit-level simulation of biosensors based on 2D semiconductors.