Thermoelectric study of crossroads material MnTe via sulfur doping

Abstract

Here, we report thermoelectric study of crossroads material MnTe via iso-electronic doping S on the Te-site. MnTe 1-x S x samples with nominal S content of x ¼ 0.00, 0.05, and 0.10 were prepared using a melt-quench method followed by pulverization and spark plasma sintering. The X-ray powder diffraction, scanning electron microscopy, and ZAF-corrected compositional analysis confirmed that S uniformly substitutes Te up to slightly over 2%. A higher content of S in the starting materials led to the formation of secondary phases. The thermoelectric properties of MnTe 1-x S x samples were characterized by means of Seebeck coefficient, electrical conductivity, and thermal conductivity measurements from 300 K to 773 K. Furthermore, Hall coefficient measurements and a single parabolic band model were used to help gain insights on the effects of S-doping on the scattering mechanism and the carrier effective mass. As expected, S doping not only introduced hole charge carriers but also created short-range defects that effectively scatter heat-carrying phonons at elevated temperatures. On the other hand, we found that S doping degraded the effective mass. As a result, the ZT of MnTe 0.9 S 0.1 was substantially enhanced over the pristine sample near 400 K, while the improvement of ZT became marginal at elevated temperatures.

Optical and Electrical Properties of α-MnTe Thin Films Deposited Using RF Magnetron Sputtering

“…The obtained carrier density of the ¡-MnTe films (8.3 © 10 18 ³1.2 © 10 19 cm ¹3 ) is higher than that of ¡-MnTe bulk samples (3³7 © 10 18 cm ¹3 ). 28,48) The film thickness dependence of the carrier density of ¡-MnTe contributed to this behavior, i.e., the carrier density of ¡-MnTe film was increased by decreasing the film thickness. 49) The ¡-MnTe films showed higher carrier density than CdTe and CIGS, which should cause high reflectance, as mentioned in section 3.3.…”

Composition and Architecture Design of Double‐Shelled Co0.85Se1−xSx@Carbon/Graphene Hollow Polyhedron with Superior Alkali (Li, Na, K)‐Ion Storage

“…[ 16 ] Therefore, the S‐dopant can invent the short‐range defects and introduce hole charge carriers, efficiently improving the intrinsic conductivity. [ 17 ] However, although the lithium‐storage performance of metal selenides is enhanced through the strategy of S‐doping, the more difficult issue of Na + /K + deintercalation has not been considered so far, which should be further investigated for the extensive application in the alkali‐ion storage. More importantly, unraveling the reaction mechanism of enhanced alkali‐ion storage by anion‐doping strategy is in great request.…”

Boosting the thermoelectric performance of Bi2O2Se by isovalent doping

“…The introduction of isoelectronic traps can effectively increase the electron concentration and improve the electrical conductivity of N ‐type Bi 2 O 2 Se. Isoelectronic elemental substitution involving great variation in electronegativity with respect to the atom of the host lattice has been an effective approach in tuning the carrier concentration of the clathrates (Sr 8 Ga 16− x In x Ge 30 ), the Zintl phase compounds (YbZn 2− x Mn x Sb 2 ) and the manganese chalcogenides (MnTe 1− x S x ) . Based on these considerations, this study was conducted to investigate the effect of isovalent La‐doping on the thermoelectric properties of Bi 2 O 2 Se.…”