Fully automated measurement setup for non-destructive characterization of thermoelectric materials near room temperature

A measurement setup is presented that allows for a complete and non-destructive material characterization of electrochemically deposited thermoelectric material. All electrical (Seebeck coefficient alpha, electrical conductivity sigma), thermal (thermal conductivity lambda), and thermoelectric (figure of merit ZT) material parameters are determined within a single measurement run. The setup is capable of characterizing individual electrochemically deposited Bi2+xTe3-x pillars of various size and thickness down to a few 10 mu m, embedded in a polymer matrix with a maximum measurement area of 1 x 1 cm(2). The temperature range is limited to an application specific window near room temperature of 10 degrees C to 70 degrees C. A maximum thermal flux of 1 W/cm(2) can be applied to the device under test (DUT) by the Peltier element driven heat source and sink. The setup has a highly symmetric design and DUTs can be mounted and dismounted within few seconds. A novel in situ recalibration method for a simple, quick and more accurate calibration of all sensors has been developed. Thermal losses within the setup are analysed and are mathematically considered for each measurement. All random and systematic errors are encountered for by a MATLAB routine, calculating all the target parameters and their uncertainties. The setup provides a measurement accuracy of +/- 2.34 mu V/K for alpha, +/- 810.16 S/m for sigma, +/- 0.13 W/mK for lambda, and +/- 0.0075 for ZT at a mean temperature of 42.5 degrees C for the specifically designed test samples with a pillar diameter of 696 mu m and thickness of 134 mu m, embedded in a polyethylene terephthalate polymer matrix. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4737880]