Highly-sensitive potassium-tantalum-niobium oxide humidity sensor

Abstract We report moisture sensitive properties of ferroelectric niobium-rich potassium tantalate K T a 0.2 N b 0.8 0.99 M n 0.01 O 3 (KTN) which shows giant humidity response with excellent reproducibility and repeatability of data as a function of exposure time and humidity contents. Many fold change in resistance was observed with change in the relative humidity (Rh) from 15% to 95% which provides maximum sensitivity (˜ 4600) at 298 K in the presence of Rh 95%. It also shows polarity dependent change in resistance with nearly 310 to 513 mV in-built potential depending on the device configuration. The polar KTN humidity sensor shows a decrease in resistance with an increase in Rh% which favors the Grotthuss mechanism responsible for humidity effects. To improve the sensitivity, a particular device configuration has implemented for the homogeneous interaction of the water vapor molecule with a maximum active sensor-surface area. The electronics with the digital display unit was designed and developed to represent the relative humidity in the form of digital display.