Effect of high copper and oxygen concentrations on the optical and electrical properties of (CdTe)xCuyOz films

Thin films of (CdTe)xCuyOz have been prepared by reactive RF cosputtering using high concentrations of copper and oxygen. The films were grown at 350 °C on glass and Si substrates. Under these conditions samples of amorphous nature were obtained with some clusters of Cu2O for the larger concentrations of Cu and O used in this work. The largest band gap variation, from 3.5 to 1.4 eV, was obtained for the samples grown with an oxygen flow of 17 standard cubic centimeters per minute (sccm) in the growth chamber. The samples are highly resistive for most cases, but for high Cu concentrations resistivities of the order of 103 Ω-cm were obtained in the case of films grown with a flow of 15 sccm of oxygen.