Narrow-band and peak responsivity enhanced metal microcavity quantum well infrared detector

The integration of narrow-band and spectral detection capabilities on pixel-level detectors is widely expected for compact infrared gas detection. This imposes great challenges on the detector performance, as the device response must precisely match with the gas absorption spectrum while also collecting enough signals in a limited spectral range to maintain high detection sensitivity. In this paper, a pixel-level narrow-band high quantum efficiency metal microcavity quantum well infrared photodetector (MC-QWIP) working around 10.6 μm is designed and fabricated. The device shows good narrow-band characteristics (200–550 nm) and high peak responsivity (at least eight times stronger than the reference device with 45° edge facet). The results of experiments and numerical simulations show that several different resonance modes with peak wavelengths close to the intrinsic detection wavelength can be obtained by changing the width of the microcavity. The response bandwidth of the device can be controlled by changing resonance modes, while the resonant wavelength can be fine-tuned by the width of the microcavity. This indicates that the MC-QWIP device has good prospects in narrow-band gas detection and narrow-band differential detection.