Breaking the interband detectivity limit with metasurface multi-quantum-well infrared photodetectors
Mel F. Hainey, Takaaki Mano, Takeshi Kasaya, Yoji Jimba, Hiroshi Miyazaki, Tetsuyuki Ochiai, Hirotaka Osato, Yoshimasa Sugimoto, Takuya Kawazu, Akitsu Shigetou, Hideki T. Miyazaki
Abstract
Since their initial demonstration, metasurface quantum-well infrared photodetectors (QWIPs)—intersubband detectors integrated with plasmon cavities—using only a single quantum well ( N w = 1) have been considered the highest performance design. However, experimental confirmation via comparison of detectors with different N w has not been performed. Here, we systematically compare N w = 1 and N w = 3 metasurface QWIPs with identical cavities and reveal the clear superiority of N w = 3 detectors. While signal (responsivity) decreases with additional wells as predicted, the signal-to-noise-ratio (detectivity) increases due to drastically reduced noise. Thanks to the narrow spectral linewidth unique to metasurface QWIPs, our detectors can reach detectivity beyond the theoretical limits of interband detectors; our best detectors show maximum detectivities of 6.4×10 10 cm Hz 1/2 /W at 7.0 μm, exceeding the interband limit of 5.3×10 10 cm Hz 1/2 /W at the same wavelength.