The SrTiO3 thin films were fabricated by pulsed laser deposition. Subsequently ion implantation with 60 keV N ions at two different fluences 1 × 1016 and 5 × 1016 ions/cm2 and followed by annealing was carried out. Thin films were then characterized for electronic structure, morphology and transport properties. X-ray absorption spectroscopy reveals the local distortion of TiO6 octahedra and introduction of oxygen vacancies due to N implantation. The electrical and thermoelectric properties of these films were measured as a function of temperature to understand the conduction and scattering mechanisms. It is observed that the electrical conductivity and Seebeck coefficient (S) of these films are significantly enhanced for higher N ion fluence. The temperature dependent electrical resistivity has been analysed in the temperature range of 80–400 K, using various conduction mechanisms and fitted with band conduction, near neighbour hopping (NNH) and variable range hopping (VRH) models. It is revealed that the band conduction mechanism dominates at high temperature regime and in low temperature regime, there is a crossover between NNH and VRH. The S has been analysed using the relaxation time approximation model and dispersive transport mechanism in the temperature range of 300–400 K. Due to improvement in electrical conductivity and thermopower, the power factor is enhanced to 15 µWm−1 K−2 at 400 K at the higher ion fluence which is in the order of ten times higher as compared to the pristine films. This study suggests that ion beam can be used as an effective technique to selectively alter the electrical transport properties of oxide thermoelectric materials.

The power factor for the Fe ion-implanted samples is greater than that of the pristine sample with a value of 700 mW m−1 K−2 at 420 K for the I1E15A sample.

Enhancement of the figure of merit (ZT) of thermoelectric materials is the topic of current research in energy studies. We report an enhancement in the thermoelectric power (TEP) of thermally evaporated PbTe thin films by low energy Ag ion implantation. This implantation results in PbTe:Ag nanocomposites. Implantations were carried out at a 130 keV Ag ion beam with ion fluences of 3 Â 10 15 , 1.5 Â 10 16 , 3 Â 10 16 , and 4.5 Â 10 16 ions/cm 2. The atomic concentrations were determined using Rutherford backscattering and found to be 1 at. %, 5 at. %, 10 at. %, and 14 at. % in the implanted PbTe films. Scanning electron microscopy images show the presence of fine cracks on the surface of as-deposited PbTe thin films that get shortened and suppressed and finally disappear at higher fluences of Ag ion implantation. The TEP measurements, from 300 K to 400 K, show $25% enhancement in the Seebeck coefficient of the Ag ion implanted films in comparison to the pristine PbTe thin film. The synchrotron based high resolution X-ray diffraction and X-ray photoelectron spectroscopy investigations reveal the formation of Ag 2 Te in the surface layer after Ag ion implantation.

The present study reports the effect of Ni ion implantation on the structural, compositional, electrical, and thermoelectric properties and electronic structures of CoSb 3 skutterudite thin films deposited on Si substrate by pulsed laser deposition. Ni ions were implanted at 200 keV in CoSb 3 thin films at three different fluences: 3 × 10 15 , 6 × 10 15 , and 1.5 × 10 16 ions/cm 2 . X-ray diffraction of Niimplanted films shows an additional phase of Co 0.75 Ni 0.25 Sb 3 . The electrical measurement of pristine films exhibits typical semiconductor behavior, while the Niimplanted films show an abrupt increase in resistivity, which may be attributed to the formation of Co 0.75 Ni 0.25 Sb 3 and material modification by the energetic ion beam. The Seebeck coefficient measurements imply that all the films are n-type with maximum Seebeck coefficient of ∼75 μV/K at ∼410 K for 2% Ni-implanted film which is about 7 times higher than the pristine CoSb 3 film. The X-ray absorption study of Ni, Co, and Sb spectrum confirms that Ni ions replace Co in the cubic frame of the skutterudite structure to form a Co 0.75 Ni 0.25 Sb 3 phase along with the distortion of crystal structure.

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