Doping-Modulated Semiconductor-to-Metal Transformation in a Low-Band-Gap Two-Dimensional Material

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) transition metal dichalcogenides (TMDCs) offer potential for advanced semiconductor devices due to their unique electronic properties.
• Modulating carrier polarity in a single 2D material system is critical for complementary metal-oxide-semiconductor (CMOS) integration but remains a significant challenge.
• Low-bandgap TMDCs are sensitive to doping and can facilitate effective polarity tuning.

Purpose of the Study:

• To investigate doping-driven transport modulation in a low-bandgap TMDC system.
• To explore the potential of dilute transition metal doping for tuning the electronic properties of PtSe2.
• To demonstrate a continuous transition of carrier polarity and conductivity within a single material platform.

Main Methods:

• Utilized five-layer platinum diselenide (PtSe2), an air-stable, low-bandgap (∼0.1 eV) TMDC.
• Incorporated dilute (∼2%) period-four transition metal dopants (V, Mn, Fe, Cr).
• Characterized transport properties, including four-terminal (4T) resistivity and carrier density, using Hall effect measurements.

Main Results:

• Achieved a continuous transition from intrinsic n-type to p-type semiconducting behavior with V and Mn doping.
• Observed a heavily p-doped regime with Fe doping.
• Demonstrated a transition to a fully metallic state with Cr doping, exhibiting low resistivity (∼200 Ω) and high hole carrier density (∼7.8 × 10^14 cm^-2).

Conclusions:

• Dilute doping of PtSe2 enables precise control over its electronic properties, spanning the entire conduction spectrum from n-type to metallic.
• This broad, doping-controlled conduction tunability within a single TMDC material is highly relevant for developing advanced CMOS technologies.
• The study highlights the potential of low-bandgap 2D semiconductors for next-generation electronic applications.