□ Professor Hyuk-Jun Kwon's research team at the Department of Electrical Engineering and Computer Science, DGIST (President Kunwoo Lee), has developed a new optical doping technology that precisely controls the electrical properties of two-dimensional (2D) semiconductors using light. This research is expected to contribute to the development of next-generation ultra-compact and high-density semiconductors, serving as a key process technology for the implementation of 2D semiconductor-based CMOS and 3D semiconductor devices in the future.
□ 2D semiconductors are drawing attention as next-generation semiconductor materials owing to their excellent electrical properties, even at extremely small thicknesses of just a few atomic layers. However, owing to their thinness, they are significantly affected by defects and surface conditions, making the desired electrical properties difficult to achieve.
□ Conventional defect control technologies for adjusting the properties of semiconductors often rely on high-temperature heat treatment, plasma processes, and electron beam irradiation. However, these methods can result in damage or defects in undesired areas. Therefore, high-precision process technology that form defects only in the desired locations at low temperatures is an urgent need.
□ The research team developed Laser-Assisted Microlens Array Processing (LAMP) to solve these problems. This technology utilizes self-assembled transparent polystyrene microparticles as small lenses to finely focus a 532 nm continuous wave laser to the sub-diffraction limit level of light. The research team successfully formed sulfur vacancies selectively within monolayer molybdenum disulfide (MoS₂) using this method.
□ Sulfur vacancy is an important defect that alters the electrical properties of MoS₂ semiconductors. The research team created this defect at precise locations using light, achieving stable n-type doping without introducing chemical impurities. This allows for precise defect control at lower energies than those required for conventional direct laser irradiation.
□ According to the experimental results, the monolayer MoS₂ transistors treated with LAMP showed up to a 63-fold increase in on-current, 51-fold improvement in field-effect mobility, and 37-fold increase in charge density compared with the untreated MoS₂. Furthermore, the treated MoS₂ was non-volatile, with the doping effect being stably maintained over an extended period, confirming its potential for application in actual semiconductor device processes.
□ Professor Hyuk-Jun Kwon stated, "This research is significant for not only enhancing semiconductor properties but also in its design of a new defect control platform that precisely forms atomic-level defects at desired locations using only light. We expect it to be widely utilized as a key local doping technology in next-generation 2D semiconductor-based CMOS and future semiconductor processes."
□ Jun-Il Kim, an integrated master’s and Ph.D. student, and Professor Hyuk-Jun Kwon were first and corresponding authors of the study, respectively. The research results were published in April 2026 in Small , a globally renowned journal in the nanotechnology field (within the top 7% of JCR). In addition, this research was supported by the Basic Science Research Program (Mid-Career) of the Ministry of Science and ICT and the Priority Research Centers Program of the Ministry of Education.
Small
High-Resolution Microlens-Assisted Tunable n-Type Optical Doping in Monolayer MoS2
18-Apr-2026