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Transparent thin-film thermocouples have been fabricated with indium tin oxide (ITO) and manganese doped indium tin oxide (Mn:ITO) as the positive and negative legs, respectively. Optical transparency of the thermocouples was above 85% in the visible region of the spectrum. Presence of Mn has been found to enhance the thermoelectric response, without significantly increasing the resistivity. Seebeck voltages of ~ 20 mV and ~ 31 mV have been obtained at 625 K, respectively, for the thermocouples with Mn:ITO legs having 1.6 at.% and 4.3 at.% Mn. The response has been found to be reproducible with an error of plusmn2%.

Correlation of charge state of Mn with the increase in resistivity with Mn concentration is demonstrated in Mn-doped indium tin oxide films. Bonding analysis shows that Mn 2p3/2 core level can be deconvoluted into three components corresponding to Mn2+ and Mn4+ with binding energies 640.8 eV and 642.7 eV, respectively, and a Mn2+ satellite at ?5.4 eV away from the Mn2+ peak. The presence of the satellite peak unambiguously proves that Mn exists in the +2 charge state. The ratio of concentration of Mn2+ to Mn4+ of ?4:1 suggests that charge compensation occurs in the n-type films causing the resistivity increase. � 2010 American Institute of Physics.

Thermopower measurements in a range of 300-650 K along with room temperature optical absorption and electrical resistivity studies were performed on indium oxide (IO) and indium tin oxide (ITO) thin films grown by reactive dc sputtering. The thermopower of as-grown and oxygen-annealed IO and ITO films measured in Ar ambient displayed characteristics attributable to oxygen loss. The observations were substantiated with optical absorption and electrical resistivity results. � 2009 IOP Publishing Ltd.

An experimental setup is developed for the measurement of the Seebeck coefficient of thin wires and thin films in the temperature range of 300-650 K. The setup makes use of the integral method for measuring the Seebeck voltage across the sample. Two pointed copper rods with in-built thermocouples serve as hot and cold probes as well as leads for measuring the Seebeck voltage. The setup employs localized heating and enables easy sample loading using a spring loaded mounting system and is fully automated. Test measurements are made on a constantan wire and indium tin oxide (ITO) thin film for illustration. The Seebeck voltage obtained for constantan wire is in agreement with the NIST data for copper constantan couple with an error of 1%. The calculated carrier concentration of ITO film from the Seebeck coefficient measurement is comparable with that obtained by electrical transport measurements. The error in the Seebeck coefficient is estimated to be within 3%. � 2008 American Institute of Physics.