Because Tl and In are known to be resonant levels in IV–VI semiconductors, here we synthesize and electrically characterize lead telluride doped $n$-type with aluminum. The results show that Al behaves as a normal donor in PbTe, reaching a maximum electron concentration of 4 10${}^{19}$ cm${}^{-3}$. At 300 K, the thermopower, when plotted as function of electron concentration (the Pisarenko relation), follows the calculated line for the conduction band of PbTe, and no enhancement is observed that could indicate the presence of a resonant level.

• Received 22 October 2011

DOI:https://doi.org/10.1103/PhysRevB.85.033204