Boosting Sensitivity and Reliability in Field‐Effect Transistor‐Based Biosensors with Nanoporous MoS2 Encapsulated by Non‐Planar Al2O3

Abstract Field‐effect transistors‐based biosensors (bio‐FETs) have been considered an important technology for label‐free and ultrasensitive point‐of‐care diagnostics. However, practical applications using bio‐FETs are limited due to the trade‐off between sensing reliability and sensitivity. This study suggests a reliable and sensitive bio‐FETs based on nanoporous molybdenum disulfide (MoS 2 ) channels encapsulated by a non‐planar high‐k aluminum oxide (Al 2 O 3 ) dielectric layer. Nanoporous MoS 2 thin film is fabricated with an abundant edge area and periodically ordered nanopores via block copolymer lithography. The ultra‐thin Al 2 O 3 dielectric layer deposited along the nanoporous structure of the MoS 2 realizes effective electrostatic control of charged biomolecules over the MoS 2 channel. In addition, it plays important roles in not only enhancing the electrical performance of the nanoporous MoS 2 bio‐FETs, that is, mobility, hysteresis, and subthreshold swing, but also achieving effective biomolecular immobilization on the device surface. The nanoporous MoS 2 channel structure surrounded by non‐planar Al 2 O 3 detects a prostate cancer biomarker with an ultra‐low limit of detection of 1 fg mL −1 . Moreover, the excellent selectivity, high sensitivity, and clinical reliability of the nanoporous MoS 2 bio‐FETs are also confirmed. The proposed device platform provides new insights and technical advances in the field of FETs based sensors for future point‐of‐care devices.