Effects of plasmon resonance on the low frequency noise and optoelectronic properties of Au/Cu codoped ZnO based photodetectors

We have investigated the effect of Au nanoparticles on the low frequency noise and current-voltage of Au/Cu doped ZnO nanoparticles (Nps) based photodetectors (PDs). Besides, 1/f noise of Cu doped ZnO is studied with and without Au Nps conditions and varied bias voltages. The Au/Cu codoped ZnO Nps showed much lower 1/f noise and higher normalized photocurrent to the dark current ratio (NPDR) than Cu doped ZnO Nps and undoped ZnO Nps. This enhancement may be attributed to the effect of localized surface Plasmon resonances (LSPR). Furthermore, the noise equivalent power represents the minimum optical power that a photodetector can distinguish from the noise and the detectivity (D*) is an important parameter in evaluating the ability of a photodetector to detect a weak signal. These parameters were determined using low frequency noise measurements. The observed low frequency noise performances could be used for Au/Cu codoped ZnO Nps based UV photodetectors.