In this work, we present studies of photoluminescence at room temperature of CdS films grown by the chemical bath deposition technique. Usually, as-grown CdS-CBD samples do not show luminescence at room temperature because of the high density of recombination centers due to many defects generated during the growth process. The change of the S/Cd ratio allows to control the density of defects giving rise to a better quality CdS-CBD films, which can show luminescence at room temperature. Depending on the S/Cd ratio, an evolution and improvement of the photoluminescence signal at room temperature is observed. (c) 2005 Elsevier B.V. All rights reserved.