Selenium thin films of thickness similar to 300 nm were deposited from a solution of sodium selenosulfate of pH 4.5. These films are amorphous, but they are crystalline and photoconductive through annealing for 15 min at 150-200 degrees C. In this paper we present the properties of these films and their use as a planar source of selenium vapor (1.7 x 10(-6) mol/cm(2) of the film) to react with metal films to form metal selenide layers. For this, metal films of Ag, Sn, In, Cu, Sb, etc., deposited by thermal evaporation, are kept in contact with the Se-thin film and are heated at temperatures typically < 350 degrees C in nitrogen. This process leads to the formation of thin films of Ag2Se, SnSe2, In2Se3, CuSe/Cu2-xSe, Sb2Se3, etc. Se-metal reaction also takes place under microwave heating. In the case of an evaporated Ag film on a chemically deposited thin film of Sb2S3, AgSbSe2 is produced through heating at 200-300 degrees C. Photovoltaic structures SnO2: F-CdS-Sb2S3-AgSbSe2 fabricated this way show open-circuit voltage > 500 mV and short-circuit current density of 2-5 mA/cm(2). (c) 2006 The Electrochemical Society.