Microstructure and thermoelectric transport properties of BiCuSeO thin films on amorphous glass substrates†
c-Axis-textured BiCuSeO thin films were grown directly on amorphous glass substrates by pulsed laser deposition. The resistivity (∼27.1 mΩ cm) of the films at room temperature was found to be much lower than those reported for polycrystalline bulk samples with the same nominal composition, and a three dimensional variable-range-hopping conduction process was suggested to govern the electrical transport properties of the films below room temperature. Moreover, detailed microstructural analysis revealed the existence of amorphous grain boundaries throughout the films, which would lead to a significant decrease of thermal conductivity. Thus, the thermoelectric performance of the present BiCuSeO thin films is expected to be greatly enhanced as compared to that of bulk samples with the same nominal composition, demonstrating the potential application in the thermoelectric thin film devices.