The electrical properties of single crystals of p-type Bi 2Te3 are shown to be tuned by annealing as-grown crystals in elemental Te vapor at temperatures in the range of 400-420 °C. While as-grown nominally stoichiometric Bi2Te3 has p-type conductivity below room temperature, Te vapor annealed Bi2Te 3 shows a cross over from p- to n-type behavior. The temperature dependent resistivity of the Te annealed crystals shows a characteristic broad peak near 100 K. Applied magnetic fields give rise to a large low temperature magnetothermoelectric effect in the Te annealed samples and enhance the low temperature peak in the resistivity. Further, Te annealed Bi2Te 3 shows a large positive magnetoresistance, ∼200% at 2 K, and ∼15% at room temperature. The annealing procedure described can be employed to optimize the properties of Bi2Te3 for study as a topological insulator.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics