A Korean research teams has successfully developed a low-temperature synthesis technology capable of directly forming high-quality two-dimensional semiconductors on ultra-thin glass and plastic substrates.

The National Research Foundation of Korea (Chairman Lee Kwang-bok) announced that a joint research team of Professor Jong-Hyun Ahn (Yonsei University, corresponding author), Professor Woon Jin Chung (Kongju National University), Professor Sungil Im (Yonsei University), Professor Kwanpyo Kim (Yonsei University), and Professor Bonggeun Song (Hongik University) had developed a low-temperature growth technology that reduced the temperature needed for the synthesis of two-dimensional semiconductor material Molybdenum disulfide (MoS2) to 150 ℃. Doctoral students Anh Tuan Hoang (Yonsei University), Luhing Hu (Yonsei University), and Beom Jin Kim (Yonsei University) led the research as first authors.

MoS2, a representative 2D semiconductor material, attracts much attention from academia due to its excellent mechanical, electrical, and optical properties. However, it was difficult to form on glass and plastic substrates because high-temperature conditions between 600 and 1000 ℃ are required for high-quality growth.

The research team succeeded in growing MoS2 at 150 ℃ by developing a low-temperature precursor used in MoS2 growth and a low-temperature MOCVD device. The team also demonstrated the possibility of a wide range of applications as flexible and wearable electronic devices by implementing high-performance transistors, logic circuits, integrated devices, and photosensors on flexible ultra-thin glass and plastic substrates without any additional transfer processes using the high-quality MoS2 semiconductor grown at low temperatures.

Also, the MoS2 grown using the team's technology has superior crystal quality and lower defect characteristics compared to the conventional high-temperature growth method, showing an advantage of a low average threshold voltage characteristic of 3.8 V, which is advantageous for low power operation when manufactured as a transistor device. In addition, the research team expects it to replace polycrystalline silicon and oxide semiconductors used in OLED display panels in the future, showing excellent average charge mobility of 9.1 cm2V-1s-1 and a high on-off ratio of 108.

Professor Ahn said about the research achievements, “The low-temperature growth technology of MoS2 not only will increase the possibility of various industrial applications, such as flexible displays and backplanes using two-dimensional materials, but also meet the temperature conditions required for semiconductor post-processing in the existing industry (400 ℃).”

The research, carried out with the support of the Leader Researcher Project and the Leading Research Center Project promoted by the National Research Foundation of Korea, was published in the international academic journal Nature Nanotechnology on July 27.

The monolayer MoS2 film grown on plastic(Parylene-C) and ultra-thin glass (UTG) substrat and stretchable integrate circuit demonstration 

[Reference] Hoang, A.T., Hu, L., Kim, B.J. et al. Low-temperature growth of MoS2 on polymer and thin glass substrates for flexible electronics. Nat. Nanotechnol. (2023)

[Main Author] Anh Tuan Hoang (Yonsei University), Luhing Hu (Yonsei University), Beom Jin Kim (Yonsei University)

* Contact email : Professor Jong-Hyun Ahn (Ahnj@yonsei.ac.kr)