Enhanced compositional contrast in imaging of nanoprecipitates buried in a defective crystal using a conventional TEM

In this article, we show that nanometer-sized precipitates of atomic numbers higher than those of the surrounding crystalline matrix can be clearly revealed in a conventional transmission electron microscope by high-angle, centered dark-field imaging after minimizing the diffraction contrast. The effect is similar to that of Z-contrast STEM, albeit with a spatial resolution limited to 1 nm. Its sensitivity to atomic number differences between precipitates and matrix is about 10, which is demonstrated for precipitates formed after Er, Ge, Cr, and Si ion implantation into SiC.