Compact Modeling of Two-Dimensional Field-Effect Biosensors

Abstract

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 MoS2 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.

Advanced Field-Effect Sensors

“…Detailed modeling able to predict the electrical response to different molecules of devices based on a variety of semiconductors is an important prerequisite for the development of performant field-effect sensors and for their integration at the circuit level. For this purpose, Pasadas and coworkers develop a compact model that predicts the electrical read-out of field-effect biosensors based on 2D semiconductors [10]. They consider electrolyte-insulator-semiconductor field-effect biosensors in which a charged, ion-permeable membrane represents the macromolecules formed by the receptors and targets attached to the insulator surface.…”

Analyzing Few-Layer and Heterostructure pH-Sensitive 2D-Material Field-Effect Transistors Using a Physics-Based SPICE Compact Model

“…The existing body of literature on the compact models for 2D-ISFETs remains notably scarce. Although El Grour et al 37 and Pasadas Cantos et al 38 have introduced models for 2D-ISFETs, both models exhibit intrinsic limitations because they are implicit in nature and rely heavily on empirical considerations. Moreover, the aforementioned ISFET models do not account for the behavior of heterostructure ISFETs.…”