A New Approach to Grow Polycrystalline CuGaSe₂ Thin Films: Chemical Vapor Deposition with I₂ as Transport Agent

Polycrystalline CuGaSe 2 thin films have been prepared onto glass by a chemical vapor deposition (CVD) method which uses iodine as the transport agent. The source material was a polycrystalline CuGaSe 2 powder which was pressed into pellets. Single phase CuGaSe 2 films were prepared in a temperature range from 460°C to 560°C and had grain sizes between 0.5 and 5 µm. Thermochemical calculations were performed for the system under equilibrium conditions to model the deposition process. The necessary values for the heat of formation H 298 and the standard entropy S 298 for CuGaSe 2 were estimated to be H 298 =-251 kJ/mol and S 298 =155 J/K mol. The calculations are in good agreement with the experimental observations.