Cu2O thin films were first deposited using magnetron sputtering at 200 degrees C. The samples produced were then annealed by a rapid thermal annealing (RTA) system at 550 degrees C in a protective atmosphere with or without the addition of oxygen. After annealing, various Cu2O and CuO films were formed. These films were characterized, as a function of oxygen concentration in RTA, using UV-VIS photometer, four-point probe, and Hall measurement system. The results show that these Cu2O thin films annealed at 550 degrees C with more than 1.2% oxygen added in the protective argon atmosphere would transform into the CuO phase. Apparently, the results of RTA are sensitive to the amount of oxygen added in the protective atmosphere. The resistivity of these Cu2O thin films decreases with the increase in the oxygen amount in the annealing atmosphere, most likely due to the increase in carrier mobility. In addition, Cu2O/ZnO (doped with AlSc) junctions were produced at 200 degrees C and annealed. The rectifying effect of P-N junction disappeared after annealing, probably due to the damage of p-n interface, which directly causes current leakage at the junction. (c) 2007 Elsevier B.V. All rights reserved.