Epitaxial growth and thermoelectric properties of c-axis oriented Bi1−xPbxCuSeO single crystalline thin films

Abstract

c-axis oriented Bi_1−xPb_xCuSeO (0 ≤ x ≤ 0.8) single crystalline thin films have been successfully epitaxially grown on SrTiO₃ (001) substrates via the pulsed laser deposition technique. Detailed X-ray diffraction and transmission electron microscopy measurements reveal the excellent c-axis and ab-plane texture of the films. As the Pb doping concentration increases, both the resistivity and the Seebeck coefficient decrease due to the increase in hole carrier concentration. The highest power factor of about 1.2 mW m⁻¹ K⁻² has been achieved in Bi_0.96Pb_0.06CuSeO single crystalline thin films at 673 K, which is much higher than those of polycrystalline ceramics with random orientation, suggesting that c-axis oriented BiCuSeO-based single crystalline thin films might have great potential for application in thermoelectric thin film devices.