Moisture contained CBD Cu(Al)/CdS bilayer films as the precursor for cation exchange and transformation into CuXS-CdS nanocomposites through air annealing

摘要

We report the effect of CdS film nucleation over ultrathin Cu and Cu/Al bilayer via chemical bath deposition, followed by air-annealing at different temperatures. X-ray diffraction pattern indicates substantial structural change, forming different phase mixtures of Cu-S compounds throughair annealingin presence of traces of moisture retained in the film. Secondary ion mass spectroscopy (SIMS) reveals the formation of CdS ad-layer over metallic Cu thin film with incrementalsurface diffusion for as prepared films. Annealing has triggered substantial diffusion and subsequent replacement of cadmium ion by copper ion from CdS crystal lattice leading to the formation of diffused composite CuxS-CdS layer. The present work has highlighted that copper being the transitional element present in the matrix of CdS would pave way for the synthesis of various CuxS compounds with wide variation of stable stoichiometric compositions as a result of ion exchange reaction.