Application of the high-pressure thermoelectric technique for characterization of semiconductor microsamples: PbX-based compounds

In this paper the technique of thermoelectric measurements at high pressure was applied for characterization of semiconductor microsamples based on lead chalcogenide compounds (p-PbSe, n-Pb1−xSnxSe). The Raman scattering technique at ambient pressure was used as an alternative tool for testing of the samples. Raman measurements have revealed broad peaks at 135 and 265 cm−1 for PbSe and Pb1−xSnxSe. Analogous spectra were obtained for PbS, and PbTe-based ternary compounds at higher and lower frequencies, respectively. The peaks have been attributed to the first- and second-order Raman modes. From resistivity and thermoelectric power data the linear decrease in the pressure of the NaCl → GeS structural phase transition with increasing Sn content has been established and the thermopower of high-pressure GeS phases have been determined. Thermoelectric properties of the samples at high pressure have shown high sensitivity to a small variation in the composition of the ternary Pb1−xSnxSe compounds, which makes it possible to distinguish semiconductor microsamples whose compositions are very similar.