Ferroelectricity-Enhanced Piezo-Phototronic Effect in 2D V-Doped ZnO Nanosheets

Emerging 2D electronic materials have shown great potential for regulating and controlling optoelectronic processes. A 2D ferroelectric semiconductor coupled with the piezo-phototronic effect may bring unprecedented functional characteristics. Here, a heterojunction photodetector made of p-Si/V-doped-ferroelectric-ZnO 2D nanosheets (FESZ-PD) is fabricated, and the ferroelectricity-enhanced piezo-phototronic effect on the photoresponse behavior of the FESZ-PD is carefully investigated. By introducing the ferroelectricity and the piezo-phototronic effect, improved current rectification performance is achieved and the photoresponse performance of the heterojunction is enhanced in a broad spectral range. The applied voltage bias during measurement naturally causes ferroelectric spontaneous polarizations to align, resulting in a change in band structure near the interface and the local piezo-phototronic effect. The modulated energy band promotes the generation, separation, and transportation efficiency of photogenerated carriers greatly. Compared with the Si/ZnO 2D nanosheets photodetector without ferroelectricity under strain-free conditions, the photoresponsivity R of the FESZ-PD increases by 2.4 times when applying a -0.20‰ compressive strain at +1 V forward bias. These results confirm the feasibility of coupling the ferroelectricity with the piezo-phototronic effect in 2D ferroelectric materials to enhance the photoresponse behavior, which provides a good way to enable the development of high-performance electronic and optoelectronic devices.