Preparation and Characterization of Ca<sub>3</sub>(Co,M)<sub>4</sub>O<sub>9+δ</sub> Type Thermoelectric Materials Using the Electrostatic Spray Deposition Method

ABSTRACTCa3(Co1−xAlx)4O9+δ, Ca3(Co1−yCuy)4O9+δ, Ca3(Co1−x−yAlxCuy)4O9+δ thin-films and sintered bodies were prepared using the electrostatic spray deposition method. Electrical conductivity of Ca3(Co0.95Al0.025Cu0.025)4O9 showed large values compared with Ca9Co12O28. Power factor of Ca3(Co0.95Al0.025Cu0.025)4O9 also showed approximately same values as those of single phase compounds of Ca9Co12O28. It was considered that the phenomenon was due to the increase of hole concentration and its mobility.