Atomic-scale quantitative elemental analysis of boundary layers in a SrTiO3 ceramic condenser by high-angle annular dark-field electron microscopy

摘要

Atomic-resolution high-angle annular dark-field (HAADF) scanning transmission electron microscopy was quantitatively performed for a boundary layer semiconducting SrTiO3 ceramic condenser which has a Bi diffusion layer near the boundary in each grain. With the aid of HAADF image simulation it was found that the Sr sites in the diffusion later are replaced by Bi atoms with a concentration of 14 at.%. In a few lattice layers near the edge of the grain, the Bi concentration abruptly increased. The Bi concentration of every Sr or Ti(O) column, along the [001] incident electron beam, was estimated from the simulation taking account of the lattice distortion, which was caused as a result of the substitution of Bi atoms, giving a high ratio of Bi to Sr and Ti atoms. It is also concluded that the simulation is indispensable for HAADF microscopy analysis of a crystal with distorted lattice. [References: 19]