Grain size effect on electrical resistivity of bulk nanograined Bi2Te3 material

The bulk nanograined Bi2Te3 material with various mean grain sizes changing from ~ 97 nm to ~ 51 nm was prepared by microwave assisted solvothermal method and hot pseudo-isostatic pressure. It was found that the specific electrical resistivity of the material increases as mean grain size decreases. Such kind of the grain effect on the resistivity can be attributed to enhanced electron scattering at the grain boundaries. The Mayadas-Shatzkes model was applied to explain experimental results. In this model the grain boundaries are regarded as potential barriers which have to be overcome by the electrons. The reflectivity R of the grain boundaries for the material under study was estimated to be equal to ~ 0.7.