ZnO p-n homojunctions have been fabricated by depositing p-type ZnO thin films using an innovative CVD method on n-type ZnO films produced by conventional D.C sputtering on glass substrates. The individual oxides have been characterized for ohmic contact by current-voltage (I-V) measurements and the semiconducting electrical parameters have been determined by resistivity and Hall effect measurements at room temperature. The formation of ZnO p-n homojunctions has been studied by I-V characteristics at 30, 300 and 400 degrees C. Rectifying nature was observed in the measured I-V curves. The ideality factor, saturation current and the barrier height for the forward bias have been calculated as a function of temperature. The improvement of the junction properties was observed from the decrease in the value of the ideality factor with the increase in temperature. A qualitative energy band diagram of the homejunction has been constructed in order to explain the interband carrier tunneling mechanism. (c) 2005 Elsevier Ltd. All rights reserved.