Preparation and Transport Properties of Bi2O2Se Single Crystals

Bi 2 O 2 Se single crystals were grown by a gas-phase transport reaction with a temperature gradient. X-ray diffraction revealed that the products crystallized in a tetragonal-type lattice with lattice parameters a = 0.38866 nm and c = 1.22001 nm. The samples were characterized by measuring the electrical conductivity, Hall coefficient, and Seebeck coefficient as functions of temperature between 80 K and 470 K. The obtained experimental data allowed us to calculate the reduced Fermi level, provided that the single-valley parabolic model applied. The corresponding value of the electron effective mass proved to be m ef ≈ 0.29. Free electron mobility is governed by the scattering of carriers by acoustic phonons.