  III-V semiconductor type-II superlattices (T2SLs) are a promising material
system with the potential to significantly reduce the dark current of, and thus
realize high-performance in, infrared photodetectors at elevated temperatures.
However, T2SLs have struggled to meet the performance metrics set by the
longstanding infrared detector material of choice, HgCdTe. Recently, epitaxial
plasmonic detector architectures have demonstrated T2SL detector performance
comparable to HgCdTe in the 77 K - 195 K temperature range. Here we demonstrate
a high operating temperature plasmonic T2SL detector architecture with
high-performance operation at temperatures accessible with two-stage
thermoelectric coolers. Specifically, we demonstrate long-wave infrared
plasmonic detectors operating at temperatures as high as 230 K while
maintaining dark currents below the "Rule 07" heuristic. At a detector
operating temperature of 230 K, we realize 22.8% external quantum efficiency in
a detector absorber only 372 nm thick ($\sim\lambda_0 /25$) with peak specific
detectivity of $2.29x10^{9}$ cm Hz$^{1/2}$ W$^{-1}$ at 9.6 $\mu$m, well above
commercial detectors at the same operating temperature.
