A Raman spectroelectrochemical investigation of chemical bath deposited CuxS thin films and their modification

Thin copper sulfide films were deposited from a chemical bath onto glass, silicon, gold and platinum substrates. Films were modified by aging the deposit under ambient conditions, annealing in air, soaking in cupric ion solution, or by fixing the electrode potential. The structure of the deposited film was investigated using neutron reflectometry, Raman scattering, electrochemistry and transmission electron microscopy. Deposited films were shown to be bilayer, with a more dense layer close to the substrate and a less dense layer at the film/solution interface. Modification resulted in the formation of a single layer film of copper sulfide, the composition determined by the extent of copper exchange/transfer with the external environment. SERS results show the presence of a ν(SS) band from the early stages of film deposition.