Degenerate and Reversible P-Type Doping of MoTe₂ Using Lewis Acid

Tuning the electronic properties of layered transition-metal dichalcogenides (TMDs) is essential for their development in electronic and optoelectronic devices. Surface charge transfer doping offers an effective method to control the carrier density. Here, MoTe 2 was successfully modified through p-type surface doping using FeCl 3, a Lewis acid, at varying concentrations. Raman spectrum and X-ray photoelectron spectroscopy (XPS) were conducted to confirm significant hole injection of MoTe 2 . Transport measurements showed that the hole concentration of FeCl 3 -modified MoTe 2 was increased to 1.8 × 10 13 cm –2, which corresponds to the degenerate doping limit. The surface functionalization of FeCl 3 leads to a more than 4 orders of magnitude increase of conductance compared to pristine MoTe 2 . Moreover, the FeCl 3 molecules can be reversibly removed via immersion in absolute ethanol, enabling selective removal of surface dopants as required and facilitating control over hole concentration. The findings highlight a viable approach for tailoring TMD properties and expanding their potential applications in next-generation technologies.