A High-resolution Colloidal Quantum Dot Imager by Monolithic Integration

Abstract Near-infrared (NIR, 0.7–1.4 µm) imagers have wide applications in night surveillance, material sorting, machine vision and potentially automatic driving. However, limited by the high-temperature processing and requirement of single-crystalline substrate, so far flip-chip is the dominant way to connect infrared photodiodes and silicon-based readout integrated circuit (ROIC) to produce infrared imagers, suffering from complicated process and ultra-high cost and hence limiting their widespread applications in the market. Here we report the monolithic integration of colloidal quantum dots (CQD) photodiodes with complementary metal-oxide-semiconductor (CMOS) ROIC, operating as a low-cost and high-performance imager. The CQD photodetector is well designed with a CMOS-compatible structure, demonstrating a response spectral range of 400–1300 nm, a detectivity of 2.1×1012 Jones at room temperature, a -3dB bandwidth of 140 kHz and a linear dynamic range over 100 dB. The CQD imager can identify materials, inspect apple scar and veins with a large size of 640×512 pixels and a spatial resolution of 40 lp/mm at a modulation transfer function of 50%. Monolithic integration significantly reduces the cost without sacrificing performance, thus providing huge potential for the ubiquitous deployment of infrared imagers.