Design of Plasmonic Coupler with Germanium Spacer Layer for Quantum Well Infrared Photodetectors

Abstract

A design of a plasmonic coupler, composed of metal hole arrays and a germanium spacer layer, integrated with a quantum well infrared photodetector structure is presented. Insertion of a germanium spacer layer in this hybrid structure enhances absorption and the z-component of an electric field in the quantum well absorption region under both substrate-side and air-side illumination configurations. By changing thickness of the germanium spacer layer, the plasmonic resonance wavelengths can be adjusted with peak quantum well response. This plasmonic coupler is believed to be promising to improve performance of quantum well infrared photodetectors.