The subject application relates to a chemical vapor (CV) deposition technique to form CuInxGa1-x(SeySi-y)2 compounds. As a copper source, solid copper can be used with a HCl transport gas and Cu3Cl3 is expected to be a major Cu-containing vapor species in this system. Liquid indium and HCl transport gas are appropriate for the indium source to provide InCl vapor species. Since selenium and sulphur are relatively highly volatile, their vapor can be carried by an inert gas without an additional transport gas, although H2Se and H2S can be used. Each source temperature can be controlled separately so as to provide a sufficient and stable vapor flux. Also provided by the subject application are CV-deposited substrates and devices, such as electronic devices or solar cells, that contain CV-deposited CuInxGaI- x(SeySi-y)2 substrates.