Effects of N₂ and O₂ annealing on the multianalyte biosensing characteristics of CeO₂-based electrolyte-insulator- semiconductor structures

A CeO₂-based multi-analyte electrolyte-insulator-semiconductor (EIS) biosensor has been fabricated on silicon substrate. To enhance the material quality and sensing performance, annealing treatment in N₂ and O₂ ambient has been incorporated. To examine the annealing effects, material analyses were conducted using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) to identify optimal treatment conditions. Furthermore, sensing performance for various ions of Na⁺, K⁺, urea, and glucose has also been tested. Results indicate that the membrane annealed at 800 C in O₂ ambience exhibited a better performance with higher multianalyte sensitivity and a lower drift rate compared with the membrane annealed in N₂ ambience. Oxygen in O₂ ambience may cause stronger reflow and fill in the oxygen vacancy so that the material properties and sensing capability can be improved in O₂ annealing ambience.