CATHODIC DEPOSITION OF COPPER SELENIDE FILMS ON TIN OXIDE IN SULFATE-SOLUTIONS

The reactions accompanying the electrodeposition of binary copper selenium compounds from cupric sulfate and selenious acid solutions were studied by voltammetry. The deposits were chemically analyzed and the formed phases were identified by x-ray diffractometry. The deposit composition is determined by the fluxes of the Cu(II) and Se(IV) species arriving at the electrode in a relatively narrow potential range, from -0.5 to -0.8 V vs. MSE. For the more negative values of potential, only Cu2Se is obtained as a solid but nonadherent compound. If there is a selenium excess, it is reduced to soluble selenide species. A model gives the distribution of the formed products as a function of the solution concentration and applied potential.