Low temperature work function variations of the Au/GaSb (110) interface: Experimental results and theoretical model

The interface formation between Au and cleaved (110) GaSb surfaces is inves tigated at low temperature (LT < 140 K) with the vibrating capacitor method . Au depositions are made in the 10(-4)-1 Angstrom range. On the lightly n- type doped sample, the work function varies by around 0.74 eV in three step s, as a function of Au coverage. We suggest possible surface state distribu tions which can explain the experimental curves. Our analysis shows that at least three acceptor states are formed at the very beginning of Au deposit ion, and before reaching one monolayer. We determine the energetic position of these states, and we propose a model to explain their density evolution . (C) 2001 American Vacuum Society.