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Plasmonic materials, and their ability to enable strong concentration of optical fields, have offered a tantalizing foundation for the demonstration of sub-diffraction-limit photonic devices. However, practical and scalable plasmonic optoelectronics for real world applications remain elusive. In this work, we present an infrared photodetector leveraging a device architecture consisting of a “designer” epitaxial plasmonic metal integrated with a quantum-engineered detector structure, all in a mature III-V semiconductor material system. Incident light is coupled into surface plasmon-polariton modes at the detector/designer metal interface, and the strong confinement of these modes allows for a sub-diffractive ($\sim <\#comment/>{\mathrm{\lambda <\#comment/>}}_0/33$) detector absorber layer thickness, effectively decoupling the detector’s absorption efficiency and dark current. We demonstrate high-performance detectors operating at non-cryogenic temperatures ($T=195\mathrm{K}$), without sacrificing external quantum efficiency, and superior to well-established and commercially available detectors. This work provides a practical and scalable plasmonic optoelectronic device architecture with real world mid-infrared applications.

 

Infrared detectors using monolithically integrated doped semiconductor “designer metals” are proposed and experimentally demonstrated. We leverage the “designer metal” groundplanes to form resonant cavities with enhanced absorption tuned across the long-wave infrared (LWIR). Detectors are designed with two target absorption enhancement wavelengths: 8 and 10 μm. The core of our detectors are quantum-engineered LWIR type-II superlattice p-i-n detectors with total thicknesses of only 1.42 and 1.80 μm for the 8 and 10 μm absorption enhancement devices, respectively. Our 8 and 10 μm structures show peak external quantum efficiencies of 45 and 27%, which are 4.5× and 2.7× enhanced, respectively, compared to control structures. We demonstrate the clear advantages of this detector architecture, both in terms of ease of growth/fabrication and enhanced device performance. The proposed architecture is absorber- and device-structure agnostic, much thinner than state-of-the-art LWIR T2SLs, and offers the opportunity for the integration of low dark current LWIR detector architectures for significant enhancement of IR detectivity. 

Remarkable systems have been reported recently using the polylithic integration of semiconductor optoelectronic devices and plasmonic materials exhibiting epsilon-near-zero (ENZ) and negative permittivity. In traditional noble metals, the ENZ and plasmonic response is achieved near the metal plasma frequency, limiting plasmonic optoelectronic device design flexibility. Here, we leverage an all-epitaxial approach to monolithically and seamlessly integrate designer plasmonic materials into a quantum dot light emitting diode, leading to a$5.6\times <\#comment/>$enhancement over an otherwise identical non-plasmonic control sample. The device presented exhibits optical powers comparable, and temperature performance far superior, to commercially available devices.

 

We demonstrate coupling to and control over the broadening and dispersion of a mid-infrared leaky mode, known as the Berreman mode, in samples with different dielectric environments. We fabricate subwavelength films of AlN, a mid-infrared epsilon-near-zero material that supports the Berreman mode, on materials with a weakly negative permittivity, strongly negative permittivity, and positive permittivity. Additionally, we incorporate ultra-thin AlN layers into a GaN/AlN heterostructure, engineering the dielectric environment above and below the AlN. In each of the samples, coupling to the Berreman mode is observed in angle-dependent reflection measurements at wavelengths near the longitudinal optical phonon energy. The measured dispersion of the Berreman mode agrees well with numerical modes. Differences in the dispersion and broadening for the different materials is quantified, including a 13 cm^-1red-shift in the energy of the Berreman mode for the heterostructure sample.