In-situ Doping of Thermoelectric Materials Based on SiGe Solid Solutions during Their Synthesis by the Spark Plasma Sintering Technique

Nanostructured SiGe:Sb solid solutions with improved thermoelectric figure of merit

“…Indeed, one would need fundamentally nonequilibrium sintering conditions to incorporate Sb impurity over the solubility level whereas Ge and Si mixing may occur in the thermal equilibrium. In particular introduction of Sb with the concentration of over 1 at.% in [7] had led to a formation of antimony clusters in the Si0.65Ge0.35 matrix accompanied with the sharp increase of the resistivity. The poor Ge and Si intermixing also leads to resistivity increase as has been shown in the present paper (Sample 1).…”

“…The measurements were carried out in the temperature range of Тm = 50-490 °С. The technology for structures fabrication, as well as all measurement techniques, are described in detail in [7,11]. Lines associated with Sb were not resolved due to low concentration.…”

“…Modern technologies such as nanostructuring provide quasi-independent control of thermoelectric coefficients, which allows one to obtain simultaneously low values of ϰ with high values of α and σ, and, thus, to increase ZT [2,3,5] In the present paper we report on the results of investigating Si0.65Ge0.35 thermoelectric structures fabricated by the technique of spark plasma sintering (SPS) of the mixture of Si, Ge and Sb powders. The SPS technique provides unique possibilities for the formation of nanostructured materials and controlling their parameters [6,7]. Feature of this work is the use of Sb impurities for fabricating the Si1-xGex, with n-type conductivity whereas in the majority of the papers As or P impurities are used.…”

Nanostructured SiGe:Sb solid solutions with improved thermoelectric figure of merit

“…In the present paper, we report on the results of the study of Si 0.65 Ge 0.35 thermoelectric structures fabricated by the spark plasma sintering (SPS) of mixture of Si, Ge and Sb powders. The SPS technique provides unique possibilities for the formation of nanostructured materials and controlling the thermoelectric coefficient as well as the parameters of nanostructuring [6,7]. The main feature of this work is the use of Sb impurities for fabricating the Si 1−x Ge x , with n-type conductivity, whereas in the majority of prior papers, As or P impurities are used.…”

“…The main feature of this work is the use of Sb impurities for fabricating the Si 1−x Ge x , with n-type conductivity, whereas in the majority of prior papers, As or P impurities are used. The advantages of antimony in comparison with P or As [1][2][3][4][5][6] are lower toxicity [7,8], in addition using Sb provides a new technological option for fabricating the n-type material. Although antimony has limited solubility in Ge and Si [9], the use of non-equilibrium fabrication techniques such as SPS allows introduction of the impurity over the solubility limit and achieving the doping concentrations sufficient for obtaining high values of ZT.…”