Scientific Achievement
Selective replacement of the top atoms of an atomically thin 2D crystal to form Janus monolayers has been achieved by hyperthermal implantation of clusters generated by laser ablation.
Significance and Impact
Hyperthermal implantation of atomically thin 2D crystals presents a new, low-temperature synthesis method to form novel Janus structures, alloys, and metastable phases that may have unique quantum properties.
Research Details
- In situ plasma diagnostics characterized and controlled the slowing of Se laser plasmas by Ar gas collisions to reveal the 3-5 eV/atom window for displacement of top-level S atoms in WS2 monolayers to form Janus WSSe monolayers.
- HAADF-STEM microscopy in tilted geometry provided unambiguous proof of Janus WSSe converted from WS2.
- First principle calculations and atomistic molecular dynamics simulations were used to understand the implantation process and confirm the measured energy thresholds.
Y.-C. Lin, C. Liu, Y. Yu, E. Zarkadoula, M. Yoon, A. A. Puretzky, L. Liang, X. Kong, Y. Gu, A. Strasser, H. M. Meyer III, M. Lorenz, M. F. Chisholm, I. N. Ivanov, C. M. Rouleau, G. Duscher, K. Xiao, and , D. B. Geohegan, “Low-energy implantation into transition metal dichalcogenide monolayers to form Janus structures,” ACS Nano, (2020), DOI: 10.1021/acsnano.9b10196.
