Synthesis of Group VIII Magnetic Transition-Metal-Doped Monolayer MoSe₂

The limitation on the spintronic applications of van der Waals layered transition-metal dichalcogenide semiconductors is ascribed to the intrinsic nonmagnetic feature. Recent studies have proved that substitutional doping is an effective route to alter the magnetic properties of two-dimensional transition-metal dichalcogenides (TMDs). However, highly valid and repeatable substitutional doping of TMDs remains to be developed. Herein, we report group VIII magnetic transition metal-doped molybdenum diselenide (MoSe₂) single crystals via a one-pot mixed-salt-intermediated chemical vapor deposition method with high controllability and reproducibility. The high-angle annular dark-field scanning transmission electron microscopy studies further confirm that the sites of Fe are indeed substitutionally incorporated into the MoSe₂ monolayer. The Fe-doped MoSe₂ monolayer with a concentration from 0.93% to 6.10% could be obtained by controlling the ratios of FeCl₃/Na₂MoO₄. Moreover, this strategy can be extended to create Co(Ni)-doped MoSe₂ monolayers. The magnetic hysteresis (M-H) measurements demonstrate that group VIII magnetic transition-metal-doped MoSe₂ samples exhibit room-temperature ferromagnetism. Additionally, the Fe-doped MoSe₂ field effect transistor shows n-type semiconductor characteristics, indicating the obtainment of a room-temperature dilute magnetic semiconductor. Our approach is universal in magnetic transition-metal substitutional doping of TMDs, and it inspires further research interest in the study of related spintronic and magnetoelectric applications.