This work presents a study on the structure of Cu-x(CdTe)(y)O-z thin films grown by reactive RF co-sputtering of Cu and CdTe targets, as a function of the Cu concentration (0.1-12 at%) and the oxygen partial pressure (P-O2) during growth (5.6 x 10(-5), 9.5 x 10(-5), 3.0 x 10(-4) and 6.4 x 10(-4) Torr). When O-2 is introduced in the growth chamber, at the two lower partial pressures and in the absence of Cu, XRD peaks of the hexagonal (H) phase are observed with increased intensity, including the (101)H peak, which becomes more intense than the normally dominant (111)C/(002)H peak; this is very rarely observed in CdTe-based films. The presence of Cu, however, tends to return the material to the crystalline state usually observed in pure CdTe films. The samples grown with higher P-O2 values, 3.0 x 10(-4) and 6.4 x 10(-4) Torr, are amorphous, regardless of the Cu concentration. (c) 2006 Elsevier B.V. All rights reserved.