□ A research team led by Prof. Jong-Soo Lee of the Department of Energy Science and Engineering at DGIST (President Kunwoo Lee), in collaboration with Principal Researcher Min-Chul Park's team at the Korea Institute of Science and Technology (KIST) and Principal Researcher Yonghoon Kim's team at the Korea institute of Materials Science (KIMS), has developed a next-generation near-infrared image sensor technology that combines quantum dots with two-dimensional semiconductors.
□ Infrared sensors that detect the short-wave infrared (SWIR) region can clearly recognize objects not only during the day and at night, but also in fog or smoke, making them a key component of future intelligent technologies such as autonomous vehicles, robotics, night surveillance, and medical imaging. However, conventional sensors are typically made using expensive semiconductor materials (e.g., InGaAs), resulting in very high fabrication costs and posing critical limitations in scaling to large-area devices.
□ To address this challenge, Prof. Jong-Soo Lee's research team proposed a hybrid photosensor architecture that combines "Ag₂Te quantum dots," which exhibit strong light absorption, with a "MoS₂ two-dimensional semiconductor," known for its exceptionally fast charge transport. The two-dimensional semiconductor compensates for the inherently slow charge transport of quantum dots, thereby maximizing the advantages of each material and presenting a new alternative.
□ In particular, the team successfully achieved significant amplification of the optical signal by employing the "photodoping" effect that occurs at the interface where the two materials meet under illumination. As a result, the developed sensor exhibited a high responsivity of 7.5 × 10⁵ A/W and a detectivity on the order of 10⁹ Jones, demonstrating excellent sensitivity capable of rapidly and accurately detecting even very weak infrared signals.
□ Furthermore, the team directly fabricated an infrared image sensor array consisting of 32 × 32 pixels beyond single-device demonstrations, confirming its capability for real image acquisition. This result demonstrates that the developed technology can be integrated with conventional CMOS-based semiconductor processes and holds strong potential for immediate commercialization as a low-cost, large-area next-generation SWIR camera and image sensor.
□ "By combining the high light-absorption characteristics of quantum dot materials with the fast charge transport properties of two-dimensional semiconductors, we were able to overcome the fundamental limitations of conventional infrared sensors," stated Prof. Jong-Soo Lee of the Department of Energy Science and Engineering at DGIST. "This technology is expected to serve as a key foundational technology for the development of high-resolution infrared cameras and next-generation intelligent photosensor systems."
□ Meanwhile, this study was supported by the Individual Basic Research Project (Mid-Career Researcher Program) of the Ministry of Science and ICT and the National Research Foundation of Korea, as well as the Creative Convergence Research Project of the National Research Council of Science and Technology. The results, recognized as a core technology in next-generation photosensors, were published in the March issue of the world-leading materials science journal Advanced Materials.
