A synergistic approach to achieving the high thermoelectric performance of La-doped SnTe using resonance state and partial band convergence

Abstract

SnTe is an alternate variant of PbTe possessing an analogous valence band(VB) pattern. However, SnTe exhibits low thermoelectric(TE) efficiency due to Sn defects triggering very high carrier concentration (n). Thus,...

Electrical Transport Properties Driven by Unique Bonding Configuration in γ-GeSe

“…The measured carrier concentration of γ-GeSe was comparable to other highly doped materials. 18,19,38 We note that this experimental result is in contrast to previous first-principles calculations, which showed that bulk γ-GeSe is a semiconductor with a bandgap of approximately 0.4 eV. 33 Figure 2d shows that the hole mobility is 12.2 cm 2 /(V s) at room temperature.…”

“…Figure c shows the thermoelectric power factor (PF = σ S 2 ) at various temperatures below 500 K. At room temperature, γ-GeSe exhibited a power factor of approximately 66.7 μW/(m K 2 ). Figure d shows a comparison of the room-temperature Seebeck coefficient and power factor of γ-GeSe with those of other group IV monochalcogenides. ,,,, The thermoelectric power factor of γ-GeSe is comparable to that of other group IV compounds. Interestingly, the Seebeck coefficient of γ-GeSe is similar to those of GeTe and SnTe but significantly different from those of other Se- or S-based monochalcogenides such as α-GeSe.…”

“…Group IV monochalcogenides (MX, M = Ge, Sn; X = S, Se, Te) are a class of materials that have recently attracted attention in research and various applications. − This family of materials is a promising candidate for applications, such as energy conversion devices and phase change memory, , owing to their intriguing electronic, thermoelectric, − and ferroelectric properties − as well as their unique bonding mechanisms. , The physical properties of group IV monochalcogenides show a strong correlation with the types of chalcogen atoms (S, Se, and Te). For example, Ge and Sn monochalcogenides with S and Se exhibit semiconducting properties, whereas monochalcogenides with Te have a small bandgap and exhibit high doping concentrations. ,− Furthermore, alloying of different chalcogenides has also been pursued to control the physical properties of this material system. ,, …”

“…Figure S7b displays the electrical conductivity and carrier concentration of some Ge monochalcogenides. [18][19][20]24 Materials with a low Ge vacancy formation energy exhibit high carrier concentration, resulting in high electrical conductivity. Elemental analysis based on energy dispersive spectroscopy (EDS) was utilized to experimentally verify the formation of Ge vacancy in γ-GeSe.…”

“…However, α-GeSe and GeS show only a moderate level of doping, which is also consistent with our interpretation. Figure S7b displays the electrical conductivity and carrier concentration of some Ge monochalcogenides. − , Materials with a low Ge vacancy formation energy exhibit high carrier concentration, resulting in high electrical conductivity.…”