Ultrabroadband Visible to Mid-wave Infrared PbS/HgTe Colloidal Quantum Dot Imagers

Photodetection over a broad spectral range is invaluable for multispectral sensing and imaging. Despite that single-element detectors with high performance and wide spectral detection ranges have been achieved with various low-dimension materials, broadband focal plane array imagers have been rarely reported. Here, we propose a stacked PbS/HgTe colloidal quantum dot photodetector configuration with graded energy gaps, which leads to an ultrabroadband spectral response from visible to mid-wave infrared (MWIR) with excellent sensitivity and detection performance. More importantly, an ultrabroadband focal plane array imager with a resolution of 640 × 512 has been fabricated and the results show low photoresponse non-uniformity (PRNU) down to 6%. The noise equivalent temperature difference (NETD) of the broadband imager is as low as 34 mK, and high-resolution thermal images have been demonstrated. With a set of optical filters, red, green, blue, short-wave infrared, MWIR, and multispectral merged images have been captured.