Homogeneous polycrystalline Si1-xGex were grown using a Si(seed)/Ge/Si(feed) sandwich structure under the low temperature gradient less than 0.4 degrees C/mm. It was found that the composition of the Si1-xGex was controlled by the growth temperature. The homogeneous Mg2Si1-xGex was synthesized by heat treatment of the homogeneous Si1-xGex powders under Mg vapor. The Mg2Si1-xGex sample with the relative density of 95% was synthesized by spark plasma sintering technique. The resistivity and the Seebeck coefficient of the Si, Ge, Si1-xGex and Mg2Si1-xGex samples were evaluated as a function of temperature. It indicated that Seebeck coefficients of the Si1-xGex and Mg2Si1-xGex samples were higher than those of Si and Ge. Moreover, the Seebeck coefficient of Mg2Si0.7Ge0.3 sample was higher than that of Mg2Si0.5Ge0.5 and Si0.5Ge0.5 samples. (C) 2011 Elsevier B. V. All rights reserved.