Reliable carbon nanotube field-effect transistors for pH sensing

Based on the inherent gain amplification ability of field-effect transistors (FETs), weak biological signals can be amplified. The present study unveils a pH sensor based on a carbon nanotube (CNT)-FET, which exhibits remarkable environmental stability. Moreover, we have successfully validated the feasibility of utilizing this CNT FET device for pH sensing, showcasing a remarkable sensitivity of Vth at 82 mV pH−1 and 87 mV pH−1 for pH ranges of 1–7 and 7–13, respectively, an extensive pH range spanning from 1 to 13, as well as minimal hysteresis measuring at 0.726 mA with pH switching loops ranging from 4.85–9.12. This research not only realizes high-performance pH sensors, but also lays the foundation for the development of FET biosensors with excellent environmental stability. This is essential to ensure that FET biosensors function properly in complex systems.