Effects of doping, electron irradiation, H+ and He+ implantation on the thermoelectric properties of Bi2Se3 single crystals

Abstract

As-grown single crystals of Bi2Se3 are doped with varying percentages of tellurium. These crystals are irradiated and implanted with electrons of energy 8 MeV and H+ and He+ ions of energy 1.26 MeV for comparative studies on their properties. Effects on the thermoelectric properties of Bi2Se3 due to high-energy electron bombardment (8 MeV), H+ and He+ ion implantation and doping are studied at temperatures ranging from 150 to 380 K. Crystal homogeneity and surface dislocations are determined using EDAX and SEM. Hot-probe and Hall effect measurements show that as-grown, electron irradiated and ion implanted crystals are n-type. Thermal diffusivity measurements prove the effective scattering mechanism (phonons) in Bi2Se3 crystals and provide a valid reason for reduced thermo-power in doped crystals.