A plasmonic infrared photodetector with narrow bandwidth absorption

Abstract

A plasmonic infrared photodetector with narrow bandwidth infrared absorption was investigated. The structure is constructed by a hydrogenated amorphous silicon (a-Si:H) film covered on a patterned Au layer consisting of the Au disk resonators and Au interdigitated electrodes on an Al2O3/Au substrate. This device exhibited narrow bandwidth infrared absorption corresponded to the localized surface plasmon resonance in the Au-disk/Al2O3/Au tri-layers resonators. The absorption of infrared energy heats up the top hydrogenated amorphous silicon film and reduces the film resistance which can be detected. The optical and electrical characteristics of the photodetector were studied. It was founded that the peak responsivities appeared at the wavelength which coincided with the localized surface plasmon resonance.