Resonant enhancement of ultra-thin long wave infrared photodetectors for high-temperature operation

Long-wave infrared (LWIR, 8–13 µm) photodetectors enable a wide range of applications in thermal imaging, spectroscopy, sensing, and communication. However, conventional LWIR photodetectors generally require thick absorbing layers and, thus, long epitaxial growth times, which increase dark current and detector noise, particularly at elevated operating temperatures. Here, we demonstrate ultra-thin LWIR photodetectors that use post-growth resonant photonic enhancement to effectively decouple the detectors’ photonic and electronic optimization. This approach strengthens and controls the interaction of incident light with ultra-thin LWIR absorbers, reducing epitaxial growth times and detector noise while allowing resonant absorption to be tuned across a range of wavelengths. We demonstrate leaky-cavity and guided-mode-resonance detectors and compare their performance with that of an otherwise identical detector without resonant enhancement. The detectors operate at temperatures up to T =230K, with specific detectivity as high as D ∗ >10 10 cm Hz /W at T =180K and D ∗ >3×10 9 cm Hz /W at T =230K. The presented detectors offer a path toward non-cryogenic LWIR sensors and imaging arrays with reduced size, weight, and power requirements for thermal imaging, industrial inspection, and multispectral chemical sensing in the long-wave infrared.