Study of a neutron-resistant p+-Si/n-ZnO photodetector with avalanching gain.

• Avalanche characteristics for p+-Si/n-ZnO heterojunction photodetector were studied. • The p+-Si/n-ZnO photodetector can well perform as a linear and fast response photodetector with good repeatability. • Neutron irradiation effects on sputtered ZnO film and p+-Si/n-ZnO photodetector were experimentally studied. The photo detection properties under large reverse bias voltage and neutron irradiation effects of the p+-Si/n-ZnO photodetector were investigated. Intrinsic defects, V O, V Zn , and O i, were observed in the non-irradiated ZnO film from the photoluminescence spectroscopy. The neutron induced defects in the neutron irradiated ZnO film reacted with the V Zn , O i and grain boundary defects resulting in the degradation of mid band emissions. The p+-Si/n-ZnO heterojunction shows a rectifying factor of >1000 at 300 K under ±1.5 V and an avalanche breakdown voltage of ∼13 V. The impact ionization process is taken place in the p+-Si region revealed from the numerical calculation of the breakdown voltage of the p+-Si/n-ZnO heterojunction. The device can well perform as a linear and fast response photodetector with good repeatability. When operating under large reverse bias voltage, the p+-Si/n-ZnO can also act as an avalanching photodiode with the avalanche gain of ∼ 30. The p+-Si/n-ZnO detector continues to be operative as an avalanche photodiode as well after neutron irradiation with the fluence of 1015 n/cm2 unless the gain degenerating to ∼10, indicating the good neutron tolerance of the p+-Si/n-ZnO photodetector. [ABSTRACT FROM AUTHOR]