Atomically Resolved Defects Modulate Electronic Structure in Plasma-Assisted 2D Janus MoSSe Monolayers
Journal
ACS Nano
Journal Volume
19
Journal Issue
50
Start Page
42365
End Page
42374
ISSN
1936-0851
1936-086X
Date Issued
2025-12-23
Author(s)
Yang, Zi-Liang
Lin, Yu-Chieh
Chaudhary, Mayur
Lin, Li-Sheng
Huang, Chih-Yang
Lin, You-Jie
Chen, Li-Chyong
Chen, Kuei-Hsien
Chueh, Yu-Lun
Abstract
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 (≈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 ≈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.
Subjects
2D materials
defect
electronic device
electronic structure
Janus
scanning tunneling microscopy
STM
Publisher
American Chemical Society (ACS)
Type
journal article