Two different device physics principles for operating MoS2 transistor biosensors with femtomolar-level detection limits

Abstract

We experimentally identify two different physics principles for operating MoS2 transistor biosensors, which depend on antibody functionalization locations. If antibodies are functionalized on an insulating layer coated on a MoS2 transistor, antibody-antigen binding events mainly modify the transistor threshold voltage, which can be explained by the conventional capacitor model. If antibodies are directly grafted on the MoS2 transistor channel, the binding events mainly modulate the ON-state transconductance of the transistor, which is attributed to the antigen-induced disordered potential in the MoS2 channel. This work advances the device physics for simplifying the transistor biosensor structures targeting for femtomolar-level quantification of biomolecules.

Assessment of three electrolyte–molecule electrostatic interaction models for 2D material based BioFETs

“…2,3,17 This layer prevents possible reactions between the ions contained in the solution and the semiconductor surface, but it reduces the electrical coupling between the device and the molecules. 27 In addition, most of the materials used as gate insulators have a hydrophilic nature that hinders the functionalization and reduces the efficiency of the bindings. 16 In ES BioFETs, the insulator layer is removed leaving the semiconductor directly in contact with the electrolyte.…”

Nanoscale Selective Passivation of Electrodes Contacting a 2D Semiconductor

“…Therefore, it is crucial to passivate the electrodes and ensure that the signal originates solely from the sensing material. The most efficient way to eliminate such electron transfer is to coat the electrodes with a nonporous insulating barrier, which completely prevents the solution from coming into contact with the electrodes . This coating has to provide good insulating properties, strong adhesion to the electrode surface and stability under the device's operating conditions.…”

Probing Electron Mobility of Monolayer MoS2 Field‐Effect Transistors in Aqueous Environments

“…[7,16,24] Upon decreasing the layer number of 2D layered materials to arrive in the ultrathin regime, the extremely large surface-to-volume ratio becomes a decisive factor affecting the electrical behavior of 2D materials, [21,25] while also inducing high sensitivity to charges in proximity to the 2D material surfaces. [16,26] Furthermore, to exploit such strong surface …”

“…[16,[26][27][28] Theoretical calculations have also demonstrated the potential use of highly scaled MoS 2 FETs as highly sensitive biological sensors for the detection of single molecules. [16,[26][27][28] Theoretical calculations have also demonstrated the potential use of highly scaled MoS 2 FETs as highly sensitive biological sensors for the detection of single molecules.…”