Resonant-cavity infrared detector with five-quantum-well absorber and 34% external quantum efficiency at 4 μm.

We report resonant-cavity infrared detectors with 34% external quantum efficiency at room temperature at the resonant wavelength of 4.0 mu m, even though the absorber consists of only five quantum wells with a total thickness of 50 nm. The full width at half maximum (FWHM) linewidth is 46 nm, and the peak absorption is enhanced by nearly a factor of 30 over that for a single pass through the absorber. In spite of an unfavorable Shockley-Read lifetime in the current material, the dark current density is at the level of state-of-the-art HgCdTe detectors as quantified by "Rule 07." The Johnson-noise limited detectivity (D*) at 21 degrees C is 7 x 10(9) cm Hz(1/2)/W. We expect that future improvements in the device design and material quality will lead to higher quantum efficiency, as well as a significant reduction of the dark current density consistent with the very thin absorber. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement