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. However, because of the low signal-to-noise ratio, it cannot be used with confidence to characterise nanostructured surfaces. Here, we show that a significant 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 pattern of a mica surface that displays rings around the Bragg spots, which reveal the existence of nanostructures on the surface.