Optimizing the spacing of Ag nanoparticle layers to enhance the performance of ZnO/Ag/ZnO/Ag/ZnO multilayer-structured UV photodetectors

In this study, the ZnO/Ag/ZnO/Ag/ZnO (ZAZAZ) multilayer-structured UV photodetectors (PDs) were fabricated and investigated with an emphasis on the effects of the spacing between the two Ag nanoparticle (NP) layers. The results indicated that embedding two Ag NP layers can significiantly improved UV PD responsivity. Owing to optimazation of the spacing between the two layers, responsivity of multilayer- structured PDs was enhanced from 11.69 to 24.32 A/W. Also, the absorption band-edges and photoresponse cutoff wavelength of ZAZAZ multilayer-structured PDs showed a significant redshift in comparition with the bare ZnO photodetector. This was ascribed to near-field effects of surface plasmons. This novel research described a creative method for increaing the performance of ZnO PDs.