Copper oxide thin films were grown by rf magnetron sputtering on glass substrates at room temperature varying the oxygen partial pressure. Using the XRD and XPS analytical measurements, the deposition condition for the formation of Cu2O and CuO phases were optimised. The optical band gap of the Cu2O and CuO was 2.31 and 1.41 eV, respectively. The bottom gate structured transparent TFTs fabricated using p-type CuO active layers operated in enhancement mode with an on/off ratio of 10(4) and field-effect mobility of 0.01 cm(2)/V s. (C) 2014 Elsevier B.V. All rights reserved.