Extended titanium nitride gate field-effect transistor with PVC selective membrane for hydrogen and potassium ion detection

A 50 nm-thick TiN sensing membrane with nitrogen (N2) ratio modification was firstly used in EGFET for pH sensing. The highest pH sensitivity of 61 mV/pH with linearity of 99.9% could be found in N2 to N2+Ar ratio of 20%. Similar performance could be maintained at least for 250 days. With additional PVC selective membrane of K+ ionophore, sensitivity could be increased to 48.7mV/pK. This developed TiN EGFET could be a potential candidate for pH and pK sensing application.