| Title |
Revisiting Ge0.9Sb0.1Te Thermoelectrics for High Temperature as a Promising Candidate for Active Cooling Applications |
| Authors |
엄유준(Yoojun Eom) ; 이창우(Changwoo Lee) ; 윤여현(Yeohyun Yoon) ; 서준교(Junkyo Seo) ; 허민수(Minsu Heo) ; 신원호(Weon Ho Shin) ; 김현식(Hyun-Sik Kim) |
| DOI |
https://doi.org/10.3365/KJMM.2026.64.5.448 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Single Parabolic Band model; GeTe; Weighted mobility; Band engineering; Thermoelectric |
| Abstract |
This study investigates the thermoelectric properties of W-doped p-type Ge0.9Sb0.1Te thermoelectric
materials using the Single Parabolic Band (SPB) model and conducts an analysis aimed at optimizing
performance at room temperature. GeTe, a type IV-VI chalcogenide semiconductor, has gained attention as
a mid-temperature (600 ~ 900 K) thermoelectric material. GeTe-based alloys are particularly utilized as ptype
thermoelectric materials at high temperatures. However, pure GeTe contains a high concentration of Ge
vacancies, leading to a high hole concentration, a low Seebeck coefficient, and high thermal conductivity,
which inherently limit its thermoelectric performance. In this study, the density-of-states effective mass (md
*),
non-degenerate mobility (μ0), weighted mobility (μW), and B-factor were calculated for Ge0.9-xWxSb0.1Te (x =
0.01-0.05) composites with varying W doping levels (x). Based on the calculations, the theoretical maximum
zT and the optimal carrier concentration were derived. Experimental results confirmed that the optimal W
doping concentration for maximizing thermoelectric performance at 325 K is x = 0.05. At this composition,
due to band convergence, md
* reached its peak. Given that the suppression of μ0 was less pronounced relative
to the increase in md
*, a maximum μW value was obtained. Additionally, the lattice thermal conductivity (κlat)
was minimized, and the B-factor reached its peak. The theoretical maximum zT at this composition was
approximately 0.91 when nH was optimized to 3.29 × 1019 cm-3, representing a 106.8% increase compared to
the pristine phase (Ge0.9Sb0.1Te, ~0.44) and a 295.7% increase compared to the x = 0.05 composition reported
by Bayikadi et al. (Ge0.85W0.05Sb0.1Te, ~0.23). And this suggests that this composition has the potential to be
utilized not only for conventional high-temperature power generation but also for active cooling applications. |