Anisotropy of the selenium diffusion coefficient in bismuth telluride Original Research Article

We present results for the anisotropic diffusion coefficient of selenium, isoelectronic impurity, in Bi2Te3 along the solidus. The single crystals were prepared by travelling heater method and they have a high crystalline quality. The experimental conditions permitted us to obtain a definite stoichiometric deviation, and diffusion profiles were obtained by SIMS. We propose a mechanism of atomic diffusion by antisite defects and thermal vacancies taking into account of the anisotropy of the diffusion coefficients.