Electrodeposition of CdTe was carried out using ammoniacal basic electrolytes containing chloride ions in order to investigate the effect of chloride ions on the electrodeposition behavior and on the properties of the resulting CdTe deposits. Photoeffect on CdTe electrodeposition, that is, the increase in the deposition rate under irradiation of white visible light onto the growing surface of the CdTe, was depressed with increasing concentration of chloride ions in the deposition bath, while all the irradiation conditions gave flat, smooth, and polycrystalline CdTe layers with almost stoichiometric composition (49.1 - 51.7 atom % Cd). Both the Cd content and crystallinity of the resulting deposits increased with increasing concentration of chloride ions in the electrolytes. The as-deposited CdTe layer prepared from the chloride electrolyte had an n-type conduction, although the CdTe layer obtained from the sulfate electrolyte was p-type, suggesting that chloride ions in the electrolyte became incorporated into the CdTe layer and formed the donor level. (c) 2006 The Electrochemical Society.