Superiority of ion irradiation over annealing for enhancing the thermopower of PbTe thin films

Present study reveals that swift heavy ion (SHI) irradiation enhances thermoelectric properties and the annealing deteriorates thermoelectric performance of PbTe thin film. X-ray diffraction (XRD), Atomic force microscopy (AFM) and Rutherford backscattering spectrometry (RBS) measurements are performed for phase formation, surface morphology and elemental composition of all the samples, respectively. Electrical conductivity (σ) and thermo power (S) measurement of all the samples have also been measured using four probe method. The increase in thermo power (S) is ∼40% upto high temperature (∼520 K) after irradiation whereas it decreases on annealing treatment. These findings are discussed on the basis of density of states enhancement or carrier scattering due to the point defects after SHI irradiation.

► PbTe thin film is synthesised, a set of film is annealed and other is irradiated. ► Oxygen desorbs during irradiation whereas increases after annealing. ► Ion beam irradiation induced defects enhances the thermoelectric power. ► Result shows superiority of ion irradiation over annealing.