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- Title
Detrimental Effects of Doping Al and Ba on the Thermoelectric Performance of GeTe.
- Authors
Srinivasan, Bhuvanesh; Gellé, Alain; Halet, Jean-François; Boussard-Pledel, Catherine; Bureau, Bruno
- Abstract
GeTe-based materials are emerging as viable alternatives to toxic PbTe-based thermoelectric materials. In order to evaluate the suitability of Al as dopant in thermoelectric GeTe, a systematic study of thermoelectric properties of Ge1−xAlxTe (x = 0–0.08) alloys processed by Spark Plasma Sintering are presented here. Being isoelectronic to Ge1−xInxTe and Ge1−xGaxTe, which were reported with improved thermoelectric performances in the past, the Ge1−xAlxTe system is particularly focused (studied both experimentally and theoretically). Our results indicate that doping of Al to GeTe causes multiple effects: (i) increase in p-type charge carrier concentration; (ii) decrease in carrier mobility; (iii) reduction in thermopower and power factor; and (iv) suppression of thermal conductivity only at room temperature and not much significant change at higher temperature. First principles calculations reveal that Al-doping increases the energy separation between the two valence bands (loss of band convergence) in GeTe. These factors contribute for Ge1−xAlxTe to exhibit a reduced thermoelectric figure of merit, unlike its In and Ga congeners. Additionally, divalent Ba-doping [Ge1−xBaxTe (x = 0–0.06)] is also studied.
- Subjects
DOPING agents (Chemistry); ALUMINUM; BARIUM; THERMOELECTRICITY; GERMANIUM telluride
- Publication
Materials (1996-1944), 2018, Vol 11, Issue 11, p2237
- ISSN
1996-1944
- Publication type
Article
- DOI
10.3390/ma11112237