Photogating-controlled ZnO photodetector response for visible to near-infrared light.

In recent years, as a direct wide band gap semiconductor, zinc oxide (ZnO) nanomaterial has attracted a lot of attention. However, the widely investigated ZnO materials are strongly limited in fast-response and broadband photodetectors due to their inherent weaknesses, so an effective structure or mechanism of ZnO nanostructure photodetector is greatly needed. In this work, a photogating-controlled photodetector based on a ZnO nanosheet-HfO-lightly doped Si architecture is demonstrated. Its performance was significantly improved by the photogating-controlled local field at the Si and HfO interfaces compared to the findings in other published works on ZnO. Consequently, the photodetector not only effectively balances the responsivity (as high as 5.6 A W) and response time (400 µs), but also broadens the wavelength response of the ZnO-based photodetectors from visible to near-infrared light range (~1200 nm). Additionally, the photogating-controlled ZnO photodetector enables high-resolution imaging both in the visible and near-infrared bands. Our photogating-controlled ZnO photodetectors not only exemplify the controllability of the gate electrode in high mobility materials but also provide a basis for the development of fast speed and high responsivity detection of high mobility materials.