Piezo-phototronic effect enhanced performance of a p-ZnO NW based UV–Vis–NIR photodetector

ZnO, as a potential candidate, has attracted extensive attention in optoelectronics, energy systems and other fields. However, the wide bandgap of ZnO severely limits its application in a wide range of photoresponse, and preparing p-type ZnO is another stumbling block that hinders the development of ZnO-based devices. Here, a high-performance photodetector with a wider spectral detection range from UV–vis to NIR builds on the structure of p-ZnO/Al₂O₃/n-Si is fabricated. The PD exhibits a marked sensitivity (75,000%), excellent responsivity (13.80 A W⁻¹, 365 nm), high specific detectivity (> 10¹² Jones), fast response (< 100 μs), which indicates that inserting an insulated Al₂O₃ layer between an n-type semiconductor and a p-type semiconductor is a fruitful method to enhance carriers separation and collection efficiency. The carrier transport mechanism at the interface of PDs with different Al₂O₃ thickness is based on the quantum mechanical of Fowler-Nordheim tunneling or direct tunneling. Additionally, the overall signal levels of the photodetector could be further optimized using the piezo-phototronic effect. This study demonstrates an alternative route to implement high-efficiency photodetectors with a broader response range and provides an in-depth understanding of regulating carrier tunneling of the p-ZnO/Al₂O₃/n-Si heterojunction using the piezo-phototronic effect.