Electronic properties of light-emitting p-n hetero-junction array consisting of p⁺-Si and aligned n-ZnO nanowires

Hetero-junction array of p⁺-Si/n-ZnO nanowires (NWs) was fabricated via contacting of aligned ZnO NWs onto a patterned p⁺-Si substrate. Current-voltage (I-V) measurement on the p-n junction showed a rectification behavior with a high rectification ratio of 10⁴ at ±3 V. In addition, the enhancement of forward current as well as the decrease of the turn-on voltage was observed with the application of negative gate bias and noticeable p-type gate dependence, which was explained in terms of asymmetric shift of the Fermi levels with gate bias in the suggested energy band diagram. Such formed hetero-junction devices showed strong UV sensitivity of 2 × 10⁴ under reverse bias of -3 V and electroluminescence in both UV and visible ranges, suggesting its potential applicability in optoelectronic devices.