Far-infrared spectroscopy of PbTe doped with iron

Far infrared reflection spectra, at room and liquid nitrogen temperature. of PbTe single crystals doped with iron are presented. Plasma minima were observed at about 160 cm(-1) and 180 cm(-1) for room and liquid nitrogen temperature, respectively Using the reflectivity diagrams and their minima, the values of the hole concentrations and their mobility at both temperatures were calculated and compared with galvanomagnetic measurements. All these results indicated that when PbTe is doped with a small concentration of Fe, the hole concentration is reduced by one order of magnitude and the free carrier mobility is larger when compared to pure PbTe.