This paper describes a two-step electrosynthesis approach for the preparation of US semiconductor layers on polycrystalline Au substrates. The sulfide ion precursor required for in situ US precipitation can be electrogenerated (via cathodic stripping) either from a pre-formed sulfur layer or a thiol-based self-assembled monolayer on the Au surface. The morphology of US formed in the two cases and the corresponding photoelectrochemical behavior are compared and contrasted. (C) 2004 Elsevier B.V. All rights reserved.