KIST develops high-performance sensor based on two-dimensional semiconductor

Next-generation imaging technology is rapidly expanding beyond smartphones into intelligent devices, robotics, extended reality (XR) devices, healthcare, CCTV, and various other industries. At the core of these technological advances are highly efficient, ultra-compact image sensors that convert light signals into electrical signals. Image sensors capture and process visual information from objects and environments, enabling precise reconstruction of their shape, size, and spatial position.

Currently, commercial image sensors are primarily based on silicon semiconductors. However, research into next-generation image sensors utilizing two-dimensional (2D) semiconductor nanomaterials -potential replacements for silicon- is actively underway. These nanomaterials, composed of atomically thin layers just a few nanometers thick, offer exceptional optical properties and miniaturization potential, making them highly suitable for high-performance image sensors. However, maximizing their performance requires low-resistance electrodes capable of efficiently processing optical signals. Conventional 2D semiconductor-based sensors face challenges in achieving low resistance electrodes, resulting in poor optical signal processing efficiency, which has been a major obstacle to commercialization.

Do Kyung Hwang (Post-Silicon Semiconductor Institute, KIST; KU-KIST Graduate School, KIST School) and Dr. Min-Chul Park (Post-Silicon Semiconductor Institute, KIST; Korea University, and Yonsei University), along with their joint research team at the Korea Institute of Science and Technology (KIST, President Sang-Rok Oh), have successfully developed an innovative electrode material called Conductive-Bridge Interlayer Contact (CBIC), enabling the realization of a 2D semiconductor-based image sensor with high optical signal efficiency. By incorporating gold nanoparticles within the electrode, the team significantly reduced its resistance, leading to a substantial improvement in the performance of 2D semiconductor image sensor. Furthermore, they effectively addressed the issue of Fermi level pinning, a common challenge in conventional electrode materials, thereby further enhancing the sensor's optical signal efficiency.

In particular, the team applied this technology to successfully implement integral imaging based three-dimensional (3D) imaging and glasses-free display technology, inspired by the compound eye structure of dragonfly. Using integral imaging technology, they achieved the acquisition and reproduction of RGB full-color 3D images, enabling the recording and reconstruction of 3D object shapes. In the future, these high-performance image sensors are expected to be widely used in various advanced industries, including XR devices, artificial intelligence (AI), and autonomous driving systems.

"By overcoming the technical limitations caused by electrode issues in existing 2D semiconductor devices, this research is expected to significantly accelerate the industrialization of next-generation imaging system technologies, which offer advantages in light absorption and miniaturization," said Dr. Do Kyung Hwang. He further emphasized the scalability of the research, stating, "The developed electrode material is easy to fabricate and scalable to large areas, making it widely applicable to various semiconductor-based optoelectronic devices." Dr. Min-Chul Park added, "2D semiconductor-based optoelectronic devices that overcome the challenge of Fermi level pinning will have a significant impact across industries that demand ultra-compact, ultra-high-resolution, and high-performance visual sensors in the future."

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KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://www.kist.re.kr/eng/index.do

This research was supported by the Ministry of Science and ICT (Minister Yoo Sang-im) and the Ministry of Culture, Sports and Tourism (Minister Yoo Yoo-chon) through the KIST Major Project, the National Research Foundation of Korea Individual Research (RS-2023-NR077025), the IITP ITRC Research and Development Project (IITP-2023-RS-00258639), and the Korea Creative Content Agency Culture and Technology Research and Development Project (R2020040080, RS-2020-KC000685). The results of this research were published online in Nature Electronics.