Multianalyte biosensor based on pH-sensitive ZnO electrolyte-insulator- semiconductor structures

Multianalyte electrolyte-insulator-semiconductor (EIS) sensors with a ZnO sensing membrane annealed on silicon substrate for use in pH sensing were fabricated. Material analyses were conducted using X-ray diffraction and atomic force microscopy to identify optimal treatment conditions. Sensing performance for various ions of Na⁺, K⁺, urea, and glucose was also tested. Results indicate that an EIS sensor with a ZnO membrane annealed at 600°C exhibited good performance with high sensitivity and a low drift rate compared with all other reported ZnO-based pH sensors. Furthermore, based on well-established pH sensing properties, pH-ion-sensitive field-effect transistor sensors have also been developed for use in detecting urea and glucose ions. ZnO-based EIS sensors show promise for future industrial biosensing applications.