An in situ half-cycle atomic layer deposition/X-ray photoelectron spectroscopy (ALD/XPS) study was conducted in order to investigate the evolution of the Al2O3 dielectric interface with InSb(1 1 1) A surfaces after sulfur passivation. A thick sulfide layer was observed to form on the as-treated surfaces, with sulfur bonded to both In and Sb. Upon annealing at 300 degrees C in the ALD reactor, the level of Sb bonded to sulfur and oxygen is below the XPS detection limit, while significant concentrations of indium oxide/sulfur states are detected. The "clean-up" of the surface oxides and sulfides by the ALD process is presented. (C) 2012 Elsevier B. V. All rights reserved.