Effect of Te doping and electron irradiation on thermal diffusivity of Bi2Se3 thin films by photo-thermal technique

Abstract

Photo-thermal beam deflection technique has been employed for the measurement of thermal diffusivity of undoped, Te doped and electron irradiated Bi2Se3 thin films. Slope from the tangential component of deflection signal with the pump-probe offset is used to evaluate the numerical value of thermal diffusivity (α). Doped and electron irradiated samples show a substantial reduction in the value of α compared to undoped sample. The variations in the thermal diffusivity of doped and electron irradiated samples are explained in terms of phonon assisted heat transfer mechanism. It is seen that α is very sensitive to structural variations arising from doping and electron irradiation. The experimentally observed results are correlated with x-ray diffraction studies.