Quantitative X-ray standing-wave phase analysis by means of photoelectrons

Quantitative information on a subsurface layer structure is obtained throug h the determination of the photoelectron escape depth by using the photoele ctrons emitted by an X-ray standing wavefield in the range of dynamical X-r ay diffraction from high-quality crystals. A simple method to determine the mean escape depth L of low-energy-loss photoelectrons is proposed, based o n the analysis of the phase of the X-ray standing wavefield in a specially designed epitaxic structure grown by molecular-beam epitaxy. The value L = 24 nm is obtained for GaSb crystals with Cu K alpha (1) radiation as a prob e. As an example of the complimentary application of the technique, an Sb-b ased single-quantum-well structure was analysed by using both high-resoluti on X-ray diffraction and the X-ray standing-wave method.