Ordered ZnO nanorods-based heterojunction light-emitting diodes with graphene current spreading layer

Ordered ZnO nanorods-based heterojunction light-emitting diodes (LEDs) have been fabricated by adopting few-layer graphene as a current spreading layer. The strong emission at low currents infers the high interfacial quality between GaN and ordered ZnO nanorods, and the current spreading effect resulting from graphene. The improved electroluminescence performance was achieved compared to the ZnO nanorods-based LED with a conventional indium-tin-oxide electrode, which can be attributed to the stable, reliable, and low resistance ohmic-contacts between graphene and ZnO nanorods, as well as the high transmittance of graphene. These results demonstrate feasibility of using graphene as electrodes for high-efficiency ZnO nanorods-based LEDs.