Synthesis, characterisation and thermoelectric properties of the oxytelluride Bi2O2Te

• Bi2O2Te crystallises in the anti-ThCr2Si2 structure type.
• Bi2O2Te is an n-type semiconductor, with a band gap of 0.23 eV.
• The thermal conductivity of Bi2O2Te approaches values found for amorphous solids.
• The thermoelectric figure of merit of undoped Bi2O2Te reaches 0.13 at 573 K.

Bi2O2Te was synthesised from a stoichiometric mixture of Bi, Bi2O3 and Te by a solid state reaction. Analysis of powder X-ray diffraction data indicates that this material crystallises in the anti-ThCr2Si2 structure type (space group I4/mmm), with lattice parameters a=3.98025(4) and c=12.70391(16) Å. The electrical and thermal transport properties of Bi2O2Te were investigated as a function of temperature over the temperature range 300≤T (K)≤665. These measurements indicate that Bi2O2Te is an n-type semiconductor, with a band gap of 0.23 eV. The thermal conductivity of Bi2O2Te is remarkably low for a crystalline material, with a value of only 0.91 W m−1 K−1 at room temperature.

Bi2O2Te, which crystallises in the anti-ThCr2Si2 structure type, is an n-type semiconductor with a remarkably low thermal conductivity. Figure optionsDownload as PowerPoint slide