THERMOELECTRIC PROPERTIES AND MICROSTRUCTURE OF FE-SI-O THIN-FILMS PREPARED BY ICB METHOD

Fe-Si-O thin films were prepared by Ionized Cluster Beam method, and the effect of oxygen content and heat treatment on their thermoelectric properties and microstructure were examined. As-deposited films were in amorphous state and they showed semiconducting properties with low Seebeck coefficients depending on the amount of oxygen in the temperature range from R. T. to 400-degrees-C. Above 450-degrees-C, migration of atoms, change of chemical bonds, and growth of microcrystals proceeded remarkably. As a result, the conductivity of the samples with a small amount of oxygen showed some enhancement and that of the samples with a large amount of oxygen showed a remarkable decrease. It is elucidated that the changes of conductivity is dependent on the amount of Si-O amorphous insulator; whether or not the conduction paths between Fe-Si microcrystals were separated by Si-O amorphous insulator caused the different conduction mechanism.