Spectral tuning of InGaAs/GaAs quantum dot infrared photodetectors with bandpass guided-mode resonance filters

Abstract

Quantum dot infrared photodetectors can be coupled with micro-structured filters to create narrowband sensors. Guided-mode resonance filters based on a high-index dielectric slab can exhibit bandpass characteristics that are suitable for monolithic integration with focal-plane arrays. Here, patterned Ge filters were integrated with InGaAs/GaAs quantum dot detectors to linearly tune their 77 K photoresponse peaks from 5.6 μm to 6.2 μm. The dark current was not influenced by these filters but the ability to narrow the photoresponse linewidth was limited by substrate scattering, which is often encountered with front-side illumination architectures.