Performance Enhancement of a ZnO-based UV Photodetector Using Patterned Ag Nanoparticles

Abstract

We studied the effect of a localized surface plasma resonance (LSPR) on ZnO-based ultraviolet photodetectors (UV-PDs) with periodic patterns of Ag nanoparticles (NPs), which had been formed by wrong a nanosphere lithography technique with a mask of polystyrene nanosphere arrays. The periodically patterned Ag NPs were positioned at the interface between the ZnO channel layer and the Si substrates, and the PD structures were constructed by forming two Al electrodes on the surface of the ZnO layer. Under λ = 365 nm UV light corresponding to the bandgap of ZnO, the photocurrent and the photoresponsivity of the ZnO UV-PDs with 100-nm-thick Ag NPs were about two times greater than those of PDs without NPs. The maximum responsivity was approximately 0.13 A/W near the 420- nm wavelength, which showed the maximum scattering efficiency. This enhanced performance of the ZnO-based UV-PDs resulting from an increase in the light absorption due to the LSPR of patterned Ag NPs.