An apparatus for simultaneous measurement of electrical conductivity and thermopower of thin films in the temperature range of 300-750 K

An automated apparatus capable of measuring the electrical conductivity and thermopower of thin films over a temperature range of 300–750 K is reported. A standard dc resistance measurement in van der Pauw geometry was used to evaluate the electrical conductivity, and the thermopower was measured using the differential method. The design of the instrument, the methods used for calibration, and the measurement procedure are described in detail. Given the lack of a standard National Institute of Standards and Technology (Gaithersburg, Md.) sample for high temperature thermopower calibration, the disclosed calibration procedure shall be useful for calibration of new instruments.