Improved and orange emission from an n-ZnO/p-Si heterojunction light emitting device with NiO as the intermediate layer

n-ZnO/p-Si heterojunction light emitting devices with and without a NiO intermediate layer were fabricated using a radio frequency magnetron sputtering system. Electroluminescence measurements revealed that the device with the NiO intermediate layer exhibits a sharper and stronger orange emission peaks at similar to 670 nm compared with that of the device without the NiO layer. And the light output-current characteristic of the n-ZnO/NiO/p-Si heterojunction device follows a nearly linear relationship (L proportional to I) rather than the superlinear relationship (L proportional to I-1.5) for the n-ZnO/p-Si heterojunction device. This work indicates that the NiO intermediate layer could effectively improve the performance of the n-ZnO/p-Si heterojunction light emitting device. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4768238]