Plasmonic-Enhanced Photodetectors for Focal Plane Arrays

Plasmonic enhancement of a quantum-dot infrared photodetector (QDIP) using a corrugated metal surface (CMS) that is fully compatible with conventional focal plane array manufacturing is demonstrated. A CMS consisting of a 2.5-μm period, 2-D square array of 1.1-μ m-high GaAs circular posts passivated with a thick Au film is fabricated into the heavily doped, top GaAs contact layer of an InAs QDIP. For substrate-side illumination, the CMS exhibits strong coupling to surface plasma waves bound to the Au/GaAs interface providing enhancement of the QDIP. At 77 K, the CMS-processed QDIP exhibits up to ~15-fold detectivity enhancement compared with the original detector.