Electrically Modulated Wavelength-Selective Photodetection Enabled by MoS2/ZnO Heterostructure

Regardless of the significant progress in photodetectors (PDs), most conventional technologies are equipped with optical filters for spectral discrimination, which results in expensive circuitry as well as a high incidence of energy loss. Different from traditional PDs, a MoS2/ZnO heterostructure-based PD is demonstrated that exhibits a bias-dependent switchable spectral response. A low-band-gap MoS2 thin film is vertically stacked on top of a high-band-gap ZnO film that allows selective charge transport from each layer by modulating the applied bias, resulting in a fine discrimination between visible and near-infrared (NIR) light. Under a lower applied bias, a dominant photoresponse in the visible region by the ZnO film is observed, whereas an enhanced response in the NIR region is obtained at higher bias, which is attributed to the generation of charge carriers in the MoS2 region. The excellent figures of merit obtained in the study attest to the high quality of the device, paving the way for fabricating energy-efficient imaging systems free of optical filters.

Automated summary

A MoS2/ZnO heterostructure-based photodetector with bias-dependent switchable spectral response is demonstrated. By vertically stacking a low-band-gap MoS2 thin film on top of a high-band-gap ZnO film and modulating the applied bias, fine discrimination between visible and near-infrared light is achieved.