Ion-Sensitive Field-Effect Transistors for Potassium Sensing

Abstract:
The development of multi-ion sensor technology based on ion-sensitive field-effect transistors (ISFETs) has the potential for a significant advancement in various domains, facilitating precise, cost-effective, and autonomous measurement processes. The present paper sets out the development and characterisation of ion-sensitive field-effect transistors (ISFETs) for potassium ion (K⁺) sensing using thin polyvinyl chloride (PVC) films embedded with K⁺ ionophores, specifically valinomycin. The ISFETs were fabricated on n-type silicon substrates with a pH-sensitive Ta2O5 layer, and the PVC membrane was applied using cyclopentanone as a safer alternative to traditional solvents. Electrical characterisation demonstrated a Nernstian response of 59 mV/pK at 20 °C for the sensors with the K⁺ sensing layer, indicating successful ion detection