Temperature effects on the performance of RuO2 thin-film pH sensor

A miniaturized pH sensor structure employing an R.F. sputtered ruthenium oxide sensing thin-film electrode in conjunction with an electroplated Ag/AgCl reference electrode is developed and the effect of the temperature of the pH test solution on the performance of the sensor is investigated. Experimental results show that the pH sensor employing 300 nm thick RuO2 sensing electrode exhibits Nernstian slopes of 65.66 mV/pH, 69.16 mV/pH, 72.50 mV/pH, 78.50 mV/pH and 84.50 mV/pH for pH test solution temperatures of 1.5 °C, 12 °C, 22 °C, 37 °C and 50 °C, respectively. The performance of the pH sensor in terms of sensitivity, response time, stability and reversibility is experimentally evaluated.