Morphology Control and Electroluminescence of ZnO Nanorod/GaN Heterojunctions Prepared Using Aqueous Solution

We report on the morphology control and electroluminescence of well-aligned ZnO nanorod/p-GaN heterojunctions prepared by an aqueous solution route at low temperature (90 degrees C). We found that the density and size of the grown nanorods and microrods depended significantly on the ZnO seed density. Synchrotron X-ray scattering measurements showed an epitaxial relationship between the ZnO nanorods and the p-GaN thin film. ZnO nanorod/p-GaN heterojunction light-emitting diodes (LEDs) with an individual chip size of 300 x 300 mu m(2) were fabricated. Room-temperature electroluminescence spectra in the visible range were obtained from the LED at forward bias voltage. This result indicates that such heterojunction LEDs fabricated from solution are a promising approach for realizing large-area light-emitting sources that have high external quantum efficiency.