Thermoelectric Properties of Ag-doped Mg2Ge Thin Films Prepared by Magnetron Sputtering

Chuang, L.; Savvides, N.; Tan, Teck Meng; Li, S.

doi:10.1007/s11664-009-1052-4

Cited by 11 publications

(7 citation statements)

References 12 publications

(11 reference statements)

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“…Following the high z T of 1.1 reported for the pseudo-binary Mg 2 Si-Mg 2 Sn system 8 , originating from mass-difference phonon scattering and conduction band convergence 8 , considerable efforts have been devoted to fabricating and characterising complex ternary 2, 13, 14 and quaternary 2, 15, 16 compounds. Whereas, binary Mg 2 Ge has received very limited attention, with only two experimental reports on n -type Sb-doped samples 12, 17 and a single report on p -type Ag-doped Mg 2 Ge thin films 18 .…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric performance of n-type Mg2Ge

Santos

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Dou

et al. 2017

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Magnesium-based thermoelectric materials (Mg2X, X = Si, Ge, Sn) have received considerable attention due to their availability, low toxicity, and reasonably good thermoelectric performance. The synthesis of these materials with high purity is challenging, however, due to the reactive nature and high vapour pressure of magnesium. In the current study, high purity single phase n-type Mg2Ge has been fabricated through a one-step reaction of MgH2 and elemental Ge, using spark plasma sintering (SPS) to reduce the formation of magnesium oxides due to the liberation of hydrogen. We have found that Bi has a very limited solubility in Mg2Ge and results in the precipitation of Mg2Bi3. Bismuth doping increases the electrical conductivity of Mg2Ge up to its solubility limit, beyond which the variation is minimal. The main improvement in the thermoelectric performance is originated from the significant phonon scattering achieved by the Mg2Bi3 precipitates located mainly at grain boundaries. This reduces the lattice thermal conductivity by ~50% and increases the maximum zT for n-type Mg2Ge to 0.32, compared to previously reported maximum value of 0.2 for Sb-doped Mg2Ge.

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Section: Introductionmentioning

confidence: 99%

Thermoelectric performance of n-type Mg2Ge

Santos

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Dou

et al. 2017

Sci Rep

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“…In addition to the fundamental benefit of nanostructuring in reducing the thermal conductivity, the rising interest for TE thin films relies in the miniaturizing ability and integration of TE modules into devices to attain a higher power density [6]. Recent works on Ag-doped Mg 2 Ge thin films deposited by magnetron co-sputtering have showed that a single-phase polycrystalline Mg 2 Ge thin films can be obtained at substrate temperatures ranging from 600 to 1000 K and exhibit power factors up to 6 × 10 −4 W K −2 m −1 at ∼600 K [7], noting that this value is still an order of magnitude lower than that of the current best commercial TE materials based on Bi 2 Te 3 .…”

Section: Introductionmentioning

confidence: 99%

Thin films of thermoelectric compound Mg2Sn deposited by co-sputtering assisted by multi-dipolar microwave plasma

Le-Quoc

Lacoste

Hlil

et al. 2011

Journal of Alloys and Compounds

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“…10−12 The binary compounds have received limited attention, however, because of their relatively low performances, especially Mg 2 Ge, with three reports on n-type bulk samples 10,13,14 and only one report on the thin film p-type Mg 2 Ge. 15 It is of great interest to understand the transport properties of these binary compounds and their interactions with the most common dopants to correctly design alloys with higher thermoelectric performance.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Fabrication Technique on the Thermoelectric Performance of Mg-Based Compounds—A Case Study of n-Type Mg₂Ge

et al. 2017

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High performance, low cost, and low toxicity have been the main characteristics associated with magnesium-based thermoelectric materials. Nevertheless, the high volatility of magnesium creates challenges in the synthesis of these materials. In this work, n-type Mg 2 Ge is synthesized using a solid-state technique, fully characterized, and compared with Mg 2 Ge fabricated through different processes. We have found that Bi is an ineffective dopant in Mg 2 Ge and precipitates into Mg 2 Bi 3 . Regardless of the technique used, the loss of Mg by evaporation and formation of precipitates in Bi-doped samples resulted in a low charge carrier concentration and, consequently, a low power factor. The precipitates significantly reduced the lattice thermal conductivity, however, leading to a figure-of-merit, zT , of 0.4 at 725 K, improving the previously reported figure-of-merit, zT , of 0.2 for Sb-doped Mg 2 Ge. This work highlights the impact of the fabrication technique on the thermoelectric performance of Mg-based compounds.

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Thermoelectric Properties of Ag-doped Mg2Ge Thin Films Prepared by Magnetron Sputtering

Cited by 11 publications

References 12 publications

Thermoelectric performance of n-type Mg2Ge

Thermoelectric performance of n-type Mg2Ge

Thin films of thermoelectric compound Mg2Sn deposited by co-sputtering assisted by multi-dipolar microwave plasma

Effect of the Fabrication Technique on the Thermoelectric Performance of Mg-Based Compounds—A Case Study of n-Type Mg₂Ge

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Thermoelectric Properties of Ag-doped Mg2Ge Thin Films Prepared by Magnetron Sputtering

Cited by 11 publications

References 12 publications

Thermoelectric performance of n-type Mg2Ge

Thermoelectric performance of n-type Mg2Ge

Thin films of thermoelectric compound Mg2Sn deposited by co-sputtering assisted by multi-dipolar microwave plasma

Effect of the Fabrication Technique on the Thermoelectric Performance of Mg-Based Compounds—A Case Study of n-Type Mg2Ge

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Effect of the Fabrication Technique on the Thermoelectric Performance of Mg-Based Compounds—A Case Study of n-Type Mg₂Ge