New information on the sublimating CdTe(001) surface from high resolution LEED

The sublimation of the CdTe(001) surface (≥ 300°C) was investigated by high-resolution low energy electron diffraction (HRLEED). From intensity oscillations of the specular diffraction spot as a function of time and energy we deduce a periodic variation of the step density, in agreement with the interpretation of earlier reflection high energy electron diffraction (RHEED) data within the step density model. However, our quantitative profile analysis shows that the relative change of the step density is only very small (≈ 15%). Thus the dominant contribution to the total desorption flux is due to step-flow, but not due to layer-by-layer sublimation. An important and general consequence is that absolute values of sublimation rates cannot be determined from intensity oscillation periods alone.