AN X-RAY-ABSORPTION SPECTROSCOPY STUDY OF THE K/GAAS(110) INTERFACE

We report the results of an X-ray Absorption Spectroscopy (XAS) investigation on the K L2,3 edges of the K/GaAs(110) interface at different coverages. The behaviour of the structure corresponding to the K 2p-->4s transition suggests a dispersed bandlike nature of the 4s-derived states from lower coverage. The two main features of the spectra, corresponding to the transition from the spin-orbit split K 2p core levels to the empty d-projected states, vary significantly with coverage. A least square fitting analysis of the XAS was possible, revealing the presence of two components that change their relative intensity and linewidth at increasing coverage. We discuss these features in terms of a final state effect in the photoabsorption process.