N-ZnO nanorod arrays/p-GaN light-emitting diodes with graphene transparent electrode

Highlights: • Monolayer graphene films are stacked to obtain better electrical conductivity. • Near UV EL is realized by inserting Al₂O₃ EBL into ZnO NRs/p-GaN LED. • Comparing to ITO-LED, G-LED shows stronger EL and exhibits good thermal stability. • Multilayer graphene films also act as a current spreading layer in the LED. -- Abstract: Few-layer graphene sheets are applied as transparent electrode and current spreading layer for n-ZnO nanorod arrays/p-GaN light-emitting diodes (LEDs). The device with graphene electrode exhibits improved electroluminescence (EL) performance in EL intensity and reliability compared to the n-ZnO nanorod arrays/p-GaN LED with conventional indium-tin-oxide (ITO) electrode. The results prove that, with its superior electrical, optical and thermal properties, graphene can be an ideal candidate for transparent electrodes in nanorod arrays-based LEDs.