Next‐Generation Two‐Dimensional FET Biosensors: Mechanistic Insights, Surface Functionalization Strategies, and Emerging Device Architectures

Abstract

Field‐effect transistor (FET) biosensors integrated with two‐dimensional (2D) materials have emerged as highly sensitive platforms for label‐free biomolecular detection. This review critically examines recent advances in 2D‐material‐based FET biosensors, focusing on graphene, transition‐metal dichalcogenides (TMDs), black phosphorus, MXenes, and related materials. Key sensing mechanisms, including electrostatic gating, charge transfer, Donnan potential, and charge scattering, are analyzed, with emphasis on the ongoing debate over the role and limitations of charge transfer in graphene‐based systems. Surface functionalization strategies and approaches to overcome the Debye screening effect, such as aptamer receptors, high‐dielectric media, and high‐frequency operation, are discussed. Emerging device architectures, including Schottky‐barrier, junctionless, split‐gate, and tunnel FETs, are reviewed for their improved sensitivity and energy efficiency. Finally, current challenges in scalability, stability, and reproducibility are addressed, along with future perspectives for the development of next‐generation 2D FET biosensors for point‐of‐care diagnostics and wearable applications.