Enhanced Performances of PVK/ZnO Nanorods/Graphene Heterostructure UV Photodetector via Piezo-Phototronic Interface Engineering

The piezo-phototronic effect can effectively engineer the energy band structure at the local interface of piezo-semiconductor junction, and thus improve the performance of optoelectronics. In this work, a high-performance poly(9-vinylcarbazole) (PVK)/ZnO nanorods/graphene heterostructure photodetector is designed and fabricated using a multi-step process. By introducing a -1.093% compressive strain to the hybrid heterostructure, carrier-dynamics modulation at the local junctions can be induced by the piezoelectric polarization, and the photoresponsivity and the specific detectivity of the photodetector can be enhanced approximate to 440% and approximate to 132% under UV light illumination with the peak values up to 80.6 A W-1 and 2.3 x 10(11) Jones, respectively. The photoresponse enhancement is attributed to the piezopotential generated at PVK/ZnO and ZnO/graphene interfaces, which promote the separation and transfer of photogenerated carriers. Physical working mechanism behind the observed results is discussed via energy band diagram. This work not only presents a new way to achieve the higher performance in photodetectors by fully utilizing piezo-phototronic interface engineering but also provides a deep understanding of piezo-phototronic effect on optoelectronic devices.