Effect of Postdeposition Annealing on the Structural and Sensing Characteristics of Tb2O3 and Tb2Ti2O7 Sensing Films for Electrolyte-Insulator-Semiconductor pH Sensors.

In this study, we proposed an electrolyte-insulator-semiconductor (EIS) device fabricating from Tb₂O₃ and Tb₂Ti₂O₇ sensing films deposited on Si substrates through reactive sputtering. The effect of different annealing temperatures (600, 700, 800, and 900°C) on the structural and surface properties of the Tb₂O₃ and Tb₂Ti₂O₇ sensing films was investigated. The performance of the Tb₂O₃ and Tb₂Ti₂O₇ sensing films as pH sensors was evaluated and correlated with the observed material properties. Compared with the Tb₂O₃ sensing film, the EIS sensor using the Tb₂Ti₂O₇ sensing film that had been annealed at 900°C exhibited better pH sensing performances, including a higher sensitivity (69.21 mV/pH), a smaller hysteresis voltage (4 mV), and a lower drift rate (0.113 mV/h) presumably the incorporation of Ti into the Tb₂O₃ to form a well-crystallized Tb₂Ti₂O₇ structure. [ABSTRACT FROM AUTHOR]