Compound semiconductor mid-wavelength infrared photodetectors operating at room temperature are the sensors of choice for demanding applications such as thermal imaging, heat-seeking, and spectroscopy. However, those detectors suffer from high dark current and thus normally require additional cooling accessories. In this work, we argue for the fundamental feasibility that by using nanowires coupled with plasmonic nano-antennae as photoabsorbers, the dark current can be largely reduced compared with typical planar devices. To demonstrate the idea, we simulate the device characteristics, such as dark current, responsivity, and detectivity, of InAsSb<sub>0.07</sub> nanowire photodetectors, and compare those properties with the best research InAs photovoltaic diodes. The results show that the designed nanowire detectors offer over one-order lower dark current and enable a peak detectivity of 7.0×10<sup>10</sup> cm Hz<sup>1/2</sup>W<sup>-1</sup> at 3.5 μm. We believe this work will provide a guidance to the design of nanowire-based MWIR photodetectors and stimulate additional experimental and theoretical research studies.
In0.53Ga0.47As/InP single photon avalanche detectors (SPADs) have a high photon detection efficiency in the near-IR, however the dark count rate is prohibitively high at room temperature. A nanowire-based In0.3Ga0.7As/GaAs SPAD can significantly reduce the DCR through a nearly three order of magnitude reduction in bulk InGaAs volume, as well as by reducing the indium composition for operation at 1064 nm. As a first step, we have successfully grown axial InGaAs/GaAs heterostructures using catalyst-free selective-area epitaxy. We will present the electrical characterization of a vertically oriented nanowire array InGaAs/GaAs SPADs operating at 1064 nm and use 3-dimensional modeling to aid in the analysis.