Oscillating low-energy electron diffraction for studying nanostructured surfaces

Low-energy electron diffraction is widely used as an efficient tool for the direct characterisation of the atomic structure of perfect surfaces. Howev er, because of the low signal-to-noise ratio, if: cannot: be used with conf idence to characterise nanostructured surfaces. Here, we show that a signif icant improvement of the diffraction data is obtained by using a modulated beam current, associated with a time correlation undertaken on a continuous sequence of digitised images. This is illustrated by the diffraction patte rn of a mica surface that displays rings around the Bragg spots. which reve al the existence of nanostructures on the surface. (C) 2000 Elsevier Scienc e B.V. AU rights reserved.