Planar platform for temperature dependent four-wire impedance spectroscopy—A novel tool to characterize functional materials

Electroceramic functional materials often need to be characterized in a sensor-like setup close to application. We present a novel sensor transducer that allows four-wire impedance spectroscopy of planar thick-film materials. Fast and easy temperature adjustment is possible by an integrated heater element. The tool can be manufactured either with Au or with Pt electrodes. The measurement of the transducers idle capacitance and calibration measurements with water covering allowed us to define a geometry factor, which is useful to determine specific materials parameters directly from the four-wire measurements. Characterization of three different kinds of materials (an n-type semiconductor, an oxygen ion-conductor and a sodium ion-conductor material) demonstrates the applicability of planar four-wire impedance spectroscopy as a powerful tool to investigate functional materials close to application.