Surface plasmon enhanced InAs-based mid-wavelength infrared photodetector

High performance photodetectors operating in the mid-wavelength infrared spectral range are of great significance in many applications such as defense, surveillance, gas sensing, and night vision. A key parameter in the design of infrared detectors is the thickness of the absorber layer; reaching high absorption with a thin absorber layer can significantly enhance the performance of the device. In this work, we demonstrate the enhancement of InAs-base infrared detectors using surface plasmon nanostructures. Experimental results show that our device exhibits broadband enhancement compared to the reference with an increase in peak responsivity of about 50%. Further analysis shows that the enhancement of the device is attributed to the near-field localization effect of the plasma structure, which is well demonstrated by the experimental dual-peak spectrum. Such mechanisms provide valuable insight into the plasmon-enhanced infrared photodetector.