Abstract
In this study, the zirconium oxide (ZrO2) membrane has been successfully applied as a pH-sensitive layer for ion-sensitive field-effect transistors (ISFETs). It exhibited an excellent response range of 56.7–58.3 mV/pH from the fixed current measurement using HP4156A. The ZrO2 membrane prepared by direct current (DC) sputtering was used as a pH-sensitive film that showed good surface adsorption with oxide and silicon. The pH sensitivities slightly decreased in 1 M NaCl solution; however, the device showed a perfect linear response of 52.5 mV/pH. The linear pH sensitivity response was measured between pH 1 to 13 in a buffer solution that was provided by Riedel–deHän.