Electrolyte-oxide-semiconductor structures as pH sensors based on resistive-switching characteristic

An electrolyte-oxide-semiconductor (EOS) structure is reported as a pH sensor in this paper, which provides a new method of pH sensing based on the resistive-switching characteristic for the first time. The concept of conductive filaments is introduced for EOS structures to explain their resistive-switching property. We find that the threshold-voltage shift in the C-V and I-V curves approximately linearly increases with the augment of electrolyte solution's pH value from 1 to 12, showing a linear sensitivity about 46.3 mV/pH. The easily fabricated EOS sensor array could provide multiple and synchronic measurements. The different reverse leakage-current phenomena of EOS sensors with different electrolytes might broaden chemical sensing applications.