Chemical vapor deposition (CVD) in an open tube system was employed to deposit single-phase CuGaSe2 thin films on plain and Mo-coated glass substrates. The use of HCl and ternary CuGaSe2 source material resulted in non-stoichiometric volatilization of the source material. The use of binary source materials - Cu2Se and Ga2Se3 - in combination with I-2 and HCl as the respective transport agents yielded single-phase CuGaSe2 thin films while the source materials were volatilized stoichiometrically. Mo/CuGaSe2/CdS/ZnO devices were fabricated from these samples exhibiting an open-circuit voltages up to V-oc = 853 mV. (C) 2001 Elsevier Science B.V. All rights reserved.