Some features of the conduction band structure, transport and optical properties of n-type Mg2Si-Mg2Sn alloys

Mg₂Si_xSn_1-x alloys are the perspective material for thermoelectric generators at moderate temperature. However the absence of reliable data on their band structure parameters does not permit to estimate a possible limit thermoelectric efficiency of these materials. According to the phase diagram there are two wide regions of solid solutions in pseudo-binary system Mg₂Si_xSn_l-x near the Mg₂Si and Mg₂Sn compounds. They are separated by a two-phase range (0.4 < x < 0.6). Here we shall report the results of the complex study of Hall and Seebeck coefficients (80 - 850 K), and optical spectra in plasma reflection interval (250 - 4500 cm^-1) for n-type samples of various composition. The properties of each composition with different x were investigated in carrier concentration range varying from 5·10¹⁸ to 5·10²⁰ cm^-3. Combined analysis of kinetic and optical properties resulted in determination of conduction band basic parameters.