We report on the fabrication of n-GaN/n-ZnO/p-GaN double heterostructure-based light-emitting diodes and their electroluminescence (EL) properties. The current-voltage characteristics of the fabricated diodes revealed rectifying behavior with a leakage current of 1.62 x 10(-5) A at -9 V, a forward current density of 1.56 x 10(-2) A at 5 V bias, and threshold and breakdown voltages of similar to 3.2 and similar to 11 V, respectively. Under forward bias an intense EL was observed, the spectrum of which depended on the injection current. From the comparison of the electroluminescence and photoluminescence spectra of the double heterostructure layers we concluded that the observed EL emission is most probably a superposition of emissions originating from ZnO, n-GaN, and p-GaN layers of the double heterostructure. (c) 2005 Elsevier Ltd. All rights reserved.