Mechanically alloyed β-Ag2Te in thermoelectric Bi2Se0.01Te2.99

• Thermoelectric compound Ag0.5Bi1.5Se0.15Te2.85 was investigated.
• Prepared by mechanical alloying from elemental Ag, Bi, Se and Ag powers.
• BiSeTe phase was obtained by graph fitting (after XRD & EDS results).
• STEM and HREM showed an unusual β-Ag2Te phase.
• β-Ag2Te phase is promising for thermoelectric and magnetoresistive applications.

We show that the thermoelectric compound Ag0.5Bi1.5Se0.15Te2.85 can be prepared by mechanical alloying from elemental Ag, Bi, Se and Ag powers. By using complementary microstructural characterization techniques, i.e. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy and energy dispersive X-ray spectroscopy, it was possible to find the exact composition of each phase formed in the compound. The phases formed were Bi2Se0.01Te2.99 and polymorphs of AgTe including an unusual β-Ag2Te phase.