Forward-current electroluminescence from GaN/ZnO double heterostructure diode

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 × 10−5 A at −9 V, a forward current density of 1.56 × 10−2 A at 5 V bias, and threshold and breakdown voltages of ∼3.2 and ∼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.