In this study, the ruthenium dioxide ( RuO2 ) thin film as sensing film of pH sensor was deposited on polyethylene terephthalate (PET) by radio frequency sputtering. The pH-sensor based on separative extended gate field effect transistor (SEGFET) was fabricated by screen-printed technology through two different fabrication methods. And the calcium ion selective membrane was dropped on sensing window of SEGFET to perform the calcium ion sensor. In addition, the difference between the two fabrication methods was studied, and the hysteresis effect of calcium ion sensor was analyzed in this study. At present, the pH-sensor has been fabricated successfully, its sensitivity and linearity are 60.36 mV/pH and 0.999 from pH1 to pH11 at 30°C, respectively. As well as the sensitivity and linearity of calcium ion sensor are 27.71 mV/pCa and 0.987 in the range of 1 M–10-4 M CaCl2 solutions, respectively.
Fiber-optic potassium ion sensor based on a novel color-changing crown ether dye.
