Electron back-scattering coefficient below 5 keV: Analytical expressions and surface-barrier effects

摘要: Simple analytical expressions for the electron backscattering coefficient, η, are established from published data obtained in ∼0.4-5 keV range 21 elements ranging Be to Au. They take into account decline η with a decrease energy E° high-Z and reverse behavior low-Z elements. The proposed (E°) lead crossing energies situated 0.4-1 keV they may be reasonably extended any of other elements—via an interpolation procedure—to metallic alloys probably compounds. influence surface barrier on escape probability back-scattered electrons is next evaluated. This evaluation provides theoretical basis explain observed deviation between various as consequence contamination or oxidation. Various practical applications strategies deduced η-measurements dedicated instruments well image interpretation low voltage scanning microscopy based backscattered detection. In this microscopy, present investigation allows generalize scarce contrast changes reversals previously multi elemental samples it suggests possibility new type contrast: work function contrast.Simple microsco...