Enhanced and persistent photoconductivity in vertical silicon nanowires and ZnS nanoparticles hybrid devices

摘要

We observe persistent photoconductivity, enhanced detectivity, responsivity, and external quantum efficiency (EQE) in hybrid ZnS nanoparticles (NPs) and vertical silicon nanowire (Si NW) devices. ZnS NPs (diameter ～30nm) were prepared by co-precipitation method. Si NWs (length ～30 μm, diameter ～30-400nm) were prepared by electroless chemical etching. Hybrid device shows ～10, 3, and 10 times enhancement of EQE, detectivity, and responsivity, respectively, as compared with the Si NWs only devices. The enhancement is attributed to presence of low refractive index ZnS around Si NWs causing funneling of photon energy into Si NWs.