Electrodeposition and optical properties of highly oriented γ-CuI thin films

A simple electrochemical process has been demonstrated to grow highly oriented γ-CuI thin films on indium doped tin oxide (ITO) glass through reducing Cu(II)-ethylene diamine tetraacetic acid disodium (EDTA) complex in aqueous solutions at or near room temperature. The CuI thin films grow preferential orientation along the <1 1 1> crystal axis from the X-ray diffraction patterns. The oriented growth of the CuI thin films is not affected by the solution pH and the applied potentials. The possible mechanism of the oriented growth is discussed, and the surface energy of different crystal planes of CuI crystal is believed to play an important role to control the oriented growth of the CuI thin films. The bandgap of the electrodeposited CuI films is 2.98 eV and the photoluminescence spectra of the CuI thin films exhibit relative intense exciton band luminescence at room temperature.