Search

Contrasts of low-voltage secondary electron microscope images have been experimentally investigated using commercial instruments having an annular type in-lens (IL) detector. The topographic and material contrasts of oxide particles on steel surfaces in the secondary electron microscope images recorded by the IL and the Everhart-Thonley detectors systematically change as a function of working distance. It is found that these two contrasts are divided using the different concentric areas of the IL detector surface. These results are discussed in terms of the kinetic energy of the detected electrons. Two simple methods for the information selection using one IL-type detector are proposed. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

AMonte Carlo simulation including surface excitation, Auger electron- and secondary electron production has been performed to calculate the energy spectrum of electrons emitted from silicon in Auger electron spectroscopy (AES), covering the full energy range from the elastic peak down to the true-secondary-electron peak. The work aims to provide a more comprehensive understanding of the experimental AES spectrum by integrating the up-to-date knowledge of electron scattering and electronic excitation near the solid surface region. The Monte Carlo simulation model of beam-sample interaction includes the atomic ionization and relaxation for Auger electron production with Casnati's ionization cross section, surface plasmon excitation and bulk plasmon excitation aswell as other bulk electronic excitation for inelastic scattering of electrons (including primary electrons, Auger electrons and secondary electrons) through a dielectric functional approach, cascade secondary electron production in electron inelastic scattering events, and electron elastic scatteringwith use ofMott's cross section. The simulated energy spectrum for Si sample describes very well the experimental AES EN(E) spectrum measured with a cylindrical mirror analyzer for primary energies ranging from 500 eV to 3000eV. Surface excitation is found to affect strongly the loss peak shape and the intensities of the elastic peak and Auger peak, and weakly the low energy backscattering background, but it has less effect to high energy backscattering background and the Auger electron peak shape. [ABSTRACT FROM AUTHOR]

It has been experimentally achieved atomic resolution imaging by using secondary electron (SE) signals in a scanning transmission electron microscope with aberration correction. The underlying physical mechanism needs to be understood and has attracted considerable theoretical interest. Several recent calculations taking account of the inner-shell ionization for high-energy SE production have not included the cascade production of low-energy SE signals which was believed to destroy the local information in SE imaging. In this work, we have developed a new theoretical method, a quantum Monte Carlo simulation, to calculate atomic resolution SE image by including every physical factor in SE generation, transportation and emission for a crystalline solid. This quantum Monte Carlo simulation method combines the Bohmian quantum trajectory method for treating electron elastic scattering and diffraction in a crystal with a conventional Monte Carlo sampling of inelastic scattering events along quantum trajectory paths. Simulation of atomic resolution SE image for atom columns in a copper crystal is performed. The contribution of the inner-shell excitation to atomic resolution SE imaging is studied. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]