Boosting sensitivity and reliability in field-effect transistor-based biosensors with nanoporous MoS${}_2$ encapsulated by non-planar Al${}_2$O${}_3$

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. (© 2023 Wiley‐VCH GmbH)