High spectrum selectivity and enhanced responsivity of a ZnO ultraviolet photodetector realized by the addition of ZnO nanoparticles layer.

A photodetector with a high spectrum selectivity and enhanced responsivity has been realized in the ZnO NPs coated Au/ZnO/Au structure. In this structure, the ZnO NPs act as the "filter" that filtrates out the short-wavelength photons to ensure the high spectrum selectivity of the photodetector, whereas on the other hand they act as the "scatterer" to scatter incident light in order to increase the absorption of the ZnO film and consequently enhance the responsivity of the photodetector. In this way, a photodetector with a response width of only 10 nm has been obtained, and the responsivity of the photodetector is 0.052 A W(-1) at 3 V at the wavelength of 376 nm, which is higher than that of the bare Au/ZnO/Au structured photodetector (0.028 A W(-1)). The results reported in this paper may provide a facile route to a highly spectrum-selective photodetector without performance degradation.