Understanding the influence of Bi/Sb substitution on carrier concentration in Mg₃Sb₂-based materials: decreasing bandgap enhances the degree of impurity ionization

Abstract

Experimental results show an intriguing phenomenon that although Bi and Sb have the same number of valence electrons, Bi/Sb substitution increases the electron concentration of n-type Mg3Sb2-based materials. Using a combination...

Realizing Excellent Structural and Thermoelectric Performance in Mg3Sb2-Based Alloys by Manipulating Mg Intrinsic Migration Kinetics with Interstitial Ni Doping

“…17 Therefore, Bi is introduced to substitute Sb and tune the band structure. 18 The Bi effect on thermoelectric performance was widely reported. For example, the Sb−Bi disorder reduces thermal conductivity through the scattering of phonons.…”

“…Mg 3 Sb 2 has a band gap of ∼0.64 eV with a peak ZT of around 716 K. − For RT applications, the band gap requires further reduction to push the peak ZT close to 300 K. Since the band edge is mainly bounded by the atomic orbitals of Mg and Sb, the band-gap energy decreases with a reducing electronegativity difference between Mg and Sb . Therefore, Bi is introduced to substitute Sb and tune the band structure . The Bi effect on thermoelectric performance was widely reported.…”