High quality Mg2Sn crystals prepared by RF induction melting

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

“…All doped films show positive Seebeck coefficients, while those of undoped films are negative, in good agreement with those results already reported for bulk materials [20,21]. Observation of a positive Seebeck coefficient for doped films corroborates well with their positive Hall voltages as revealed by Hall effect measurements and thus validates the role of Ag impurity as p-dopant.…”

“…The values of electrical conductivity and Seebeck coefficient for both doped and undoped stoichiometric Mg2Sn films (i.e. films deposited with Ag-doped Sn targets or pure Sn targets biased at −250 V) are in good agreement with reported results for Ag-doped and undoped bulk polycrystalline Mg2Sn [20,21]. In fact, for the target-substrate distance of 120 mm, film with stoichiometric Mg2Sn shows the highest power factor, which is ∼4.35 × 10 −3 W K −2 m −1 .…”

“…comparable to that of Bi2Te3-based thermoelectric compounds. Considering the fact that deposited thin films have polycrystalline nature and exhibit nano-size crystallites we could expect a lower thermal conductivity than that of the same materials in single crystalline or polycrystalline bulk form, which is about 5-7 W m −1 K −1 [21]. The best figure of merit ZT at room temperature of the deposited thin films thus should be better than 0.3.…”

Electronic structure and thermoelectric properties of p-type Ag-doped Mg2Sn and Mg2Sn1-xSix (x = 0.05, 0.1)

“…Adding too much excess Mg leads to the formation of a MgþMg 2 Sn eutectic phase, while too little excess Mg leads to the formation of a Sn þ Mg 2 Sn eutectic phase. 10 This precludes us from using adjustments in the Mg/Sn ratio to try to force the Ag atoms onto one lattice site or the other. To be consistent, we label our samples (Mg 1-y Ag y ) 2 Sn or (Mg 1-y Ag y ) 2 Sn 1-x Si x as if the Ag was substituting for Mg, a fact we will justify a posteriori.…”

“…Ag-doped p-type Mg 2 Sn material has been studied by Savvides and co-workers. 10 Ag is also an acceptor in Mg 2 Si. 11 Isoda et al 12 studied double-doping Mg 2 Sn 0.75 Si 0.25 with Ag and Li and prepared their samples by liquid solid reaction followed by hot pressing.…”