Tuning of the Thermoelectric Properties of Bi₂Te₃ Nanorods Using Helium Ion Irradiation

Abstract

The present study reports an enhancement of the power factor of Bi 2 Te 3 nanorods NRs) by helium (He + ) ion irradiation. High-resolution transmission electron microscopy studies revealed the formation of amorphous layers on the surface of the NRs at the high ion fluence. This amorphous nature is due to the accumulation of migrating point defect clusters at the surface of the NRs. Raman scattering experiments provide further insight to the observed structural modifications. At higher ion fluence, impurity-dominated scattering processes significantly enhance the value of the Seebeck coefficient of Bi 2 Te 3 NRs. The He + ion irradiation up to the ion fluence of 1 × 10 16 ions/cm 2 improves the thermoelectric transport properties with the highest power factor, 8.2 μW/m K 2 , at 390 K. Further investigations may result in the possibility of fabricating the Bi 2 Te 3 NRs as thermoelectric generators with a high power factor for space applications.

Isotropic Thermoelectric Performance of Layer-Structured n-Type Bi2Te2.7Se0.3 by Cu Doping

“…This strategy effectively increases the β factor and thus thermoelectric performance, as demonstrated in many materials GeTe, PbTe, and Bi 2 Te 3 . , Minimizing the independent parameter κ L is also efficient for β factor enhancement. Effective methods include introducing defects (including point defects, − dislocation, and interface) and nanostructures. − …”

Defect Induced Unconventional Ferromagnetism in Au Intercalated Bi2Se3 Nanocrystals for Spintronic Applications

“…Therefore, phonons away from the Brillouin zone center can also contribute to Raman spectra. [ 30 ] An additional broad peak at ≈ 250 cm −1 appears for the Au‐implanted sample, which is completely absent in the pristine Bi 2 Se 3 sample. With the increase in fluence, this peak evolves into two distinct peaks at 233 and 250 cm −1 , which can be assigned to the trigonal Se (t‐Se) and amorphous Se (a‐Se), respectively.…”

“…This observation is consistent with the previously reported result for the Raman study for He + ion implanted Bi 2 Te 3 . [ 30 ]…”

“…reported the enhancement of power factor and Seebeck coefficient in Bi 2 Te 3 nanorods with He + ion irradiation up to the fluence of 1 $$\times \nobreakspace \nobreakspace 10^{16}$$ ions cm −2 due to impurity dominated scattering as evidenced by Raman measurement. [ 30 ]…”

The effect of charged particle irradiation on the transport properties of bismuth chalcogenide topological insulators: a brief review

“…41 However, at energies below 1 MeV, no type conversion occurs in Bi 2 Te 3 even at fluences as high as ∼10 17 cm −2 . 49 In the case of n-type Bi 2 Se 3 , type conversion has not been achieved through point defect creation. However, implantation of n-type Bi 2 Se 3 with Ca + ions at relatively low energy (0.2 meV) and fluence (∼10 14 cm −2 ) has been found to cause type conversion owing to charge doping caused by the non-isovalent Ca + ions.…”