ConceptEM: a new method to quantify solute segregation to interfaces or planar defect structures by analytical TEM and applications to inversion domain boundaries in doped zinc oxide

Abstract

Multiple scattering of electrons within the specimen degrades the spatial resolution in scanning or nano-probe transmission electron microscopy (TEM). It also reduces significantly the chemical signal from a local defect. Hence, the accuracy of analytical TEM is much lower than its sensitivity. A new technique has been developed for determining small amounts of solute atoms incorporated into well-defined planar defects in solids. The method is based on recording series of analytical spectra taken with different electron beam diameters centered above a defect which is oriented nearly edge-on. A linear least-squares fit is performed and the segregation level determined from the slope of the fitting curve. This concept of nearly concentric electron probes in analytical TEM (conceptEM) can be applied to both energy-dispersive X-ray (EDX) or electron energy-loss spectroscopy (EELS). For the study a nano-probe mode is used but no scan unit is needed. Reliability and accuracy have been modeled and applications to doped ZnO are presented.