Practical aspects of atomic resolution imaging and analysis in STEM

In the scanning transmission electron microscope (STEM), the spatial resolu tion of experimental images and spectra is determined by the size and stabi lity of the electron probe. Atomic resolution, of 0.2 nm and under, is poss ible if all experimental parameters influencing probe formation are careful ly optimized. Here, the formation and alignment of the STEM probe using ele ctron Ronchigrams is described. Practical examples of probe formation, Z-co ntrast imaging and electron energy-loss spectroscopy (EELS) are demonstrate d on a Schottky field emission, JEOL JEM-2010F microscope. Single crystal S i [1 1 0] images were used for resolution testing and showed that probe siz es of under 0.14 nm are obtainable. A 36.5 degrees Sigma 5 tilt grain bound ary in nominally iron doped SrTiO3 was imaged incoherently and analyzed wit h EELS, using this probe. (C) 1999 Elsevier Science B.V. All rights reserve d.