Effective Area Effects on the Final Device Sensitivity of Ion Sensor Transducers

Abstract

Fluorine-doped tin oxide (SnO 2 :F) was used as the ion-sensing layer of an EGFET-pH sensor. The effective area affects the final results, as well as the sensor surface potential and sensitivity. The sensor miniaturization is highly required on medical applications, with that the effective area must be properly understood. Routine insertion and removal of total and partial surface areas in buffer solution were analyzed and compared. The results show that the routine changes considerable the sensor sensitivity. Variations in the double layer, Helmholtz plane, and Gouy-Chapman region play a significant role. The final sensitivities of the samples were compared with values available in the literature, even for other materials. The role that area normalization plays in quality assessment is discussed for proper future technological miniaturizations.