Molybdenum as a versatile dopant in SnTe: a promising material for thermoelectric application

Abstract

Electronic structure engineering of SnTe by doping with molybdenum results in an increase in the band gap, valence band convergence, introduction of resonance levels, Rashba splitting and multiband transport, leading to enhanced thermoelectric performance.

A case of perfect convergence of light and heavy hole valence bands in SnTe: the role of Ge and Zn co-dopants

“…The band structure of a material plays a major role in its transport properties. 18,29 The electronic structure of Sn 16 Te 16 displays a direct band gap of 0.08 eV at the G point; energy offsets of 0.30 eV and 0.24 eV were observed between the light hole and heavy hole valence bands and light electron and heavy electron conduction bands, respectively (Fig. 1(a)).…”

“…48 A rigid band and a constant scattering time approximation were considered during the study in the temperature range of 300 to 800 K as reported previously. 29,30,41 Using eqn (1) and (2), we determined the electrical conductivity and the Seebeck coefficient. 30,49…”

“…3(c)). 29,30 Fig. 3(d) shows four prominent peaks in 'sS 2 ' values with two each on either side of the Fermi level indicating that the material could be tuned to act as either p-type or n-type depending on where the Fermi level resides.…”

“…In order to decrease this energy-offset and increase the band degeneracy, several dopants such as Ag, Ca, Cd, Mg, Mo, V, and W have been used. 13,[18][19][20][21][22][23][24][25][26][27][28][29][30] These dopants are also known to increase the band gap of SnTe leading to inhibition of the bipolar effect. The band effective mass (m b ) is also increased by distorting the DOS near the Fermi level by the addition of resonant dopants like In, Zn and Bi.…”

Influence of structure phase transition on the thermoelectric properties of Cu2Se1−xTex liquid-like compounds

“…2 To maximize the ZT value of materials, larger power factor (S 2 s) and lower thermal conductivity (k) of materials are required. 3 The Seebeck coefficient can be improved by some methods such as resonance doping, 4,5 band convergence, 6 hyperconvergence, 7,8 Rashba splitting, 9 band gap enlargement, 10,11 and breaking of crystal mirror symmetry. 12 The balance between low effective mass and high mobility of charge carriers can enhance their electrical conductivity.…”