THERMOELECTRIC-POWER STUDIES ON 1-PERCENT EXCESS TE DOPED PB0.8SN0.2TE THIN-FILMS

Thin films of Pb0.8Sn0.2Te of thicknesses varying between 360 Angstrom and 3400 Angstrom have been prepared by flash evaporation on cleaned glass substrates held at room temperature. Thermoelectric power (TEP) of these films has been evaluated by measuring the thermal emi developed by the integral method in the temperature range 300 K to 500 K. It has been found that TEP of all the films is positive and increases with temperature in the low temperature region and tends to saturate at high temperatures. beyond 400 K. This has been attributed to the pinning of the Fermi level at high temperatures. It was also found that these films did not show the expected linear dependence of TEP on the inverse film thickness.