View article

It has been shown that the accuracy of pH sensor devices based on insulator/electrolyte interface is limited by a slow response, which manifests itself as hysteresis and drift. In this paper, we use hysteresis measurement to compare the performance of Ta₂O₅ and Si₃N₄ as pH-sensing surfaces. The results depend on the time taken to perform a complete pH loop. At short loop times (960-9600 s) Ta₂O₅ is superior to Si₃N₄ is reduced. These data can be combined with earlier measurements of the hysteresis of Al₂O₃ surfaces to establish the following order to hysteresis magnitude at a loop time of 1920 s: si₃N₄ > Al₂O₃ > Ta₂O₅.