Broadband photodetector material integrating day-night recognition and distance measurement

A research team in South Korea has developed a next-generation sensor material capable of integrating the detection of multiple light wavelengths.

A joint research team led by Dr. Wooseok Song at the Korea Research Institute of Chemical Technology (KRICT) and Professor Dae Ho Yoon at Sungkyunkwan University successfully developed a new broadband photodetector material that can sense a wider range of wavelengths compared to existing commercial materials, and achieved cost-effective synthesis on a 6-inch wafer-scale substrate.

Photodetectors are typically divided into different categories depending on the wavelength range they detect, serving applications in smart devices, security, environmental monitoring, and healthcare. Until now, separate sensors for visible, near-infrared (NIR), mid-infrared (MWIR), and long-wave infrared (LWIR) were required. For example, autonomous vehicles or military drones needed to mount multiple sensors for different functions. Broadband photodetectors, however, integrate multiple wavelength ranges into a single sensor. Conventional broadband sensors based on two-dimensional (2D) materials could only detect from visible to NIR wavelengths, while MWIR and LWIR detection was limited, and their poor stability under humidity and temperature variations hindered outdoor or defense applications.

The newly developed broadband photodetector material detects the full spectrum from visible to LWIR and maintains stability even under high-temperature and high-humidity conditions. This allows product designs to be simplified and production costs reduced by replacing multiple sensors with a single integrated device. For instance, an autonomous vehicle or military drone could integrate visible-light sensors (for daytime imaging and recognition), NIR sensors such as LiDAR (for distance measurement), and MWIR/LWIR sensors (for night-time human detection) into one.

The team utilized a topological crystalline insulator (SnSe₀.₉Te₀.₁), derived from the 2D semiconductor tin selenide (SnSe) with tellurium (Te) substitution. As a quantum material, TCIs exhibit a narrow band gap, enabling detection of long-wavelength light such as MWIR and LWIR, while also maintaining high stability. Unlike conventional 2D semiconductors that cannot detect low-energy photons due to a wide band gap, the TCI structure allows electrons to move freely on the surface states, enabling broadband and highly sensitive detection—including subtle LWIR thermal radiation such as that emitted by human fingers.

As a result, this new material achieves broadband detection over an ~8× wider range (0.5–9.6 μm), compared to conventional 2D semiconductors (0.4–1.2 μm). It is also thin, lightweight, and highly stable under high temperature, humidity, and even underwater conditions.

Another key advantage is the simplified and low-cost fabrication process. While traditional TCI synthesis required expensive ultra-high-vacuum equipment such as molecular beam epitaxy (MBE), the research team designed SnSe₀.₉Te₀.₁ to retain topological properties while being less sensitive, enabling cost-efficient solution-based thermal decomposition synthesis. This allowed uniform production on a palm-sized 6-inch wafer, which is compatible with existing semiconductor processes, making it favorable for large-scale manufacturing.

The team is now extending this technology to 8-inch or larger wafers and integrating sensor arrays and circuits to develop complete sensor modules.

Dr. Wooseok Song explained, “This sensor can cover applications ranging from autonomous vehicles and military drones to smartwatches and home IoT security systems.”

KRICT President Young-Kuk Lee emphasized, “This breakthrough will mark a turning point in replacing expensive imported broadband sensors and usher in an era of high-performance, domestically produced broadband sensors.”

This research was published in ACS Nano (Impact Factor: 16.0) in July 2025. Dr. Wooseok Song (KRICT) and Professor Dae Ho Yoon (Sungkyunkwan University) served as corresponding authors, with Do Hyung Lee and Hyeong-Ku Jo of KRICT as first authors.

 

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KRICT is a non-profit research institute funded by the Korean government. Since its foundation in 1976, KRICT has played a leading role in advancing national chemical technologies in the fields of chemistry, material science, environmental science, and chemical engineering. Now, KRICT is moving forward to become a globally leading research institute tackling the most challenging issues in the field of Chemistry and Engineering and will continue to fulfill its role in developing chemical technologies that benefit the entire world and contribute to maintaining a healthy planet. More detailed information on KRICT can be found at https://www.krict.re.kr/eng/

The study was supported KRICT’s Basic Research Program and the Nano/Materials Technology Development Program of the National Research Foundation of Korea, funded by the Ministry of Science and ICT.

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