Thermoelectric properties of single-crystallinethin films of ITO and series (ZnO)_mIn₂O₃ grownby reactive solid-phase epitaxy

S. Ohta¹, H. Ohta², M. Hirano², H. Hosono^2,3,K. Koumoto¹

¹Department of Applied Chemistry,Graduate School of Engineering, Nagoya University, JAPAN

²Hosono Transparent ElectroActiveMaterials, ERATO, JST KSP C-1232, 3-2-1 Sakado, Takastu, Kawasaki 213-0012,JAPAN

³Materials and StructuresLaboratory, Tokyo Institute of Technology,4259 Nagatsuta, Midori, Yokohama226-8503, JAPAN

Recently,n-type oxide thermoelectric materials that show a high performance areintensely required. We measured thermoelectric properties, such as electricalconductivity and Seebeck coefficient, of single-crystalline thin films of ITOand (ZnO)_mIn₂O₃ (where m is integer)fabricated by the reactive solid-phase epitaxy (R-SPE) method at roomtemperature to high temperatures in Ar. The negative Seebeckcoefficents indicate that these materials are n-type conductors. Moreovers theelectrical conductivity of these materials shows the value far higher than1,000Scm^-1. This value is quite high compared to other n-type bulkoxide materials, though the Seebeck coefficient is rather small. Single crystaldata obtained in the present study would give us an insight into the upperlimit of thermoelectric performance of the wide band-width n-type oxides.