Reconfigurable FET Biosensor for a Wide Detection Range and Electrostatically Tunable Sensing Response

Abstract

The nanoscale field effect transistors have emerged as promising candidates for highly sensitive bio/chemical detection. Despite the massive progress, current FET biosensing technologies have limitations in terms of adaptability, versatility and throughput. Herein, we present an approach to dynamically tune the sensing performance of a FET biosensor by local electrostatic gating of the metal-semiconductor junctions. Depending upon the bias applied at the local gates, the device switches its operation configurations to deliver functionalities with markedly different sensing characteristics. Such reconfigurability at the runtime allows application suitability on the go, a feature non-existent in the state-of-art FET biosensors. The results of numerical simulations, based on framework validated against the experimental results, reveal promising sensing performance in terms of a high detection sensitivity (~105) with 104-fold tunable sensitivity window and a wide overall dynamic range spanning >4 orders of magnitude using a single device (a ~100-fold improvement over a conventional FET biosensor). The wide dynamic range is also established through a simple analytical approach based on 1:1 binding kinetics for antibody-antigen system. Taken together, the results strongly suggest that the proposed sensor design, representing the first approach of purely electrostatic phenomenon based tuning of sensing performance, has a considerable potential to enable the future development of more compact, multifunctional and adaptive biosensing platforms.