Janus transition metal dichalcogenides, such as MoSSe, are potential materials for advanced electronics, yet their real-world device performance often fails to meet theoretical expectations. The origin of this discrepancy, rooted in atomic-scale imperfections, has remained critically unexplored. Here, using scanning tunneling microscopy and spectroscopy, this work provides atomic-scale insights into the complex electronic structures of monolayer Janus MoSSe, revealing distinct defect species that govern device performance. The residual sulfur dopants are found to introduce a broad band (approximate to 0.5 eV) of shallow in-gap states near the valence band with spatially inhomogeneous distribution. Moreover, this work unveils two distinct native charge defects with spatially electronic influence extending approximate to 2.5 nm: conductive charge traps that reduce the local effective bandgap by more than half and insulating scattering centers that impede carrier transport. This microscopic understanding of defect-induced electronic modifications explains how atomic-scale imperfections influence macroscopic device limitations, providing fundamental design criteria for the engineering of Janus devices.
- Atomically Resolved Defects Modulate Electronic Structure in Plasma-Assisted 2D Janus MoSSe Monolayers
- Zi-Liang Yang - Natl Taiwan Univ, Grad Sch Adv Technol, Taipei 10617, TaiwanYu-Chieh Lin - Supreme Council Of HealthMayur Chaudhary - Natl Tsing Hua Univ, Dept Mat Sci & Engn, Hsinchu 30013, TaiwanLi-Sheng Lin - National Taiwan UniversityChih-Yang Huang - Natl Taiwan Univ, Ctr Atom Initiat New Mat, Taipei 10617, TaiwanYou-Jie Lin - Natl Tsing Hua Univ, Dept Mat Sci & Engn, Hsinchu 30013, TaiwanJyh-Pin Chou - National Taiwan UniversityLi-Chyong Chen - Natl Taiwan Univ, Dept Phys, Taipei 10617, TaiwanKuei-Hsien Chen - Natl Taiwan Univ, Ctr Condensed Matter Sci, Taipei 10617, TaiwanYu-Lun Chueh - National Tsing Hua University, College of Semiconductor ResearchYa-Ping Chiu - Supreme Council Of Health
- American Chemical Society
- 10
- 114L900803 / Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education in Taiwan 113-2119-M-002-014-MBK / National Science and Technology Council 114L104312 / Academia Sinica; Academia Sinica - Taiwan 114L104312 / National Taiwan University 112H1007-C06 / Taiwan Semiconductor Manufacturing Company-National Taiwan University Joint Research Center
- Journal article
- 23/12/2025
- ACS nano, Vol.19(50), pp.42365-42374
- English