Electroluminescence enhancement of ZnO nanorod array/GaN heterojunction with MgZnO barrier layer

ZnO nanorod arrays were fabricated by solution method, and highly vertical-oriented ZnO NRA were obtained with MgxZn1-xO seed layer. The temperature-dependent photoluminescence showed a typical transformation process between bound exciton to free exciton emission, causing a domination of near-band edge photoluminescence at room temperature. For ZnO NRA/GaN heterojunction device, an obvious blue light could be observed after current injection, and electroluminescence profiles originated from ZnO exciton, ZnO/GaN interface and GaN accepter related recombination could be enhanced due to the increasing current injection. By introducing MgZnO barrier layer, the interface state on ZnO side could be effectively passivated, and tunneling effect through the barrier could significantly enhance the recombination probability, achieving high efficiency electroluminescence comparing with heterojunction without MgZnO barrier layer.