ZnO nanorods-graphene hybrid structures for enhanced current spreading and light extraction in GaN-based light emitting diodes

One-dimensional and two-dimensional hybrid structures, composed of vertical ZnO nanorods grown on large-area graphene, are successfully integrated onto the GaN/InGaN light emitting diodes (LEDs). Compared with GaN LED without transparent conducting electrode, current injection and light emission increased almost 2-3 times, respectively, by the introduction of graphene based conducting electrode. Additional similar to 66% increase in light emission was achieved by growing the ZnO nanorods on the graphene, which is consistent with the finite difference time domain modeling result. Furthermore, electroluminescence intensity profiles confirm the uniform light emission with high brightness in GaN LED with the ZnO nanorods-graphene hybrid electrode. (C) 2012 American Institute of Physics. [doi:10.1063/1.3683484]