Some features of the conduction band structure, transport and optical properties of n-type Mg/sub 2/Si-Mg/sub 2/Sn alloys

Mg/sub 2/Si/sub x/Sn/sub 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 Mg/sub 2/Si/sub x/Sn/sub l-x/ near the Mg/sub 2/Si and Mg/sub 2/Sn 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/sup -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/spl middot/10/sup 18/ to 5/spl middot/10/sup 20/ cm/sup -3/. Combined analysis of kinetic and optical properties resulted in determination of conduction band basic parameters.