ABSOLUTE MEASUREMENT OF NORMALIZED THICKNESS, T LAMBDA(I), FROM OFF-AXIS ELECTRON HOLOGRAPHY/

A simple method is described for determination of the quantity t/lambd a(i) from off-axis electron holograms, where t is the local thickness and lambda(i) is the mean-free-path for inelastic scattering of high e nergy electrons. The method uses the energy-filtered amplitude reconst ructed from a hologram and, when applied to samples with well characte rized geometry, allows measurement of the inelastic mean-free-path. Me asured values of 71 +/- 5 nm for MgO and 92 +/- 7 nm for Si for 100 ke V beam energy compare favorably with calculated and experimental value s from electron-energy-loss spectroscopy. Differences between the two techniques for determining t/lambda(i) and the utility of the holograp hic method are briefly discussed.