Ultra-Thin All-Epitaxial Plasmonic Detectors

Plasmonics, offering strong concentration of optical fields and the opportunity for sub-diffraction-limit photonic devices, has long been core to the field of nanophotonics. However, practical and scalable plasmonic optoelectronics for real world applications remain elusive. In this work we demonstrate a plasmonic infrared photodetector leveraging an all-epitaxial device architecture consisting of a 'designer' plasmonic metal integrated with a quantum-engineered detector structure, all in a mature III-V semiconductor material system. By coupling incident light into surface plasmon-polariton modes in our detector, we decouple the detector's absorption efficiency and dark current, enabling our detectors to operate at non-cryogenic temperatures (T = 195 K) and out-perform the current state-of-the-art long wave infrared detector (HgCdTe). Our detectors achieve peak external quantum efficiencies of 39% at 10.42 $\mu$m and dark currents >50% below HgCdTe, all in a 311 nm (~$\lambda_0$/33) absorber region. These results are particularly timely, as environmental restrictions related to mercury and cadmium have driven a search for HgCdTe detector alternatives. Leveraging the environmentally-safe, all-epitaxial plasmonic-optoelectronic architecture, we demonstrate state-of-the-art performance from sub-diffraction-limit thickness devices at wavelengths of vital importance for a range of sensing and imaging applications.