Cadmium sulfide (CdS) thin films were electrochemically formed on polycrystalline Au films, using electrochemical atomic layer deposition (E-ALD) and successive ionic layer adsorption reaction (SILAR). In developing a E-ALD cycle for CdS, voltammetric studies of the individual precursors on Au electrodes were used to determine potentials ranges for the underpotential deposition (upd) of Cd and S. Subsequent potential optimization was performed by nanofilm growth, systematically varying the deposition potential of one element and examining the resulting Cd/S stoichiometry using electron probe micro-analysis, and microscopy of deposit morphology. Optimized deposits displayed a linear growth dependence on cycle number, characterized using spectroscopy ellipsometry, and expected for an ALD process. The 1LO Raman peak was observed at 303 cm(-1) using 514 nm light. The X-ray diffraction pattern was consistent with a strongly preferred zinc blend < 111 > orientation. For SILAR deposits, formed using the same flow system used for E-ALD, the CdS existed as porous clusters, as viewed using SEM, whereas E-ALD deposits were conformal and compact coatings. The comparison between E-ALD and SILAR deposits, formed using the flow cell system, indicated some degree of homogeneous precipitation near the surface in the case of SILAR, which appeared to be eliminated using the E-ALD growth cycle, leading to both a higher growth rate and film quality. (C) 2018 Elsevier Ltd. All rights reserved.