Metallic Transport in Monolayer and Multilayer Molybdenum Disulfides by Molecular Surface Charge Transfer Doping

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanoscience

Background:

• Carrier modulation in transition-metal dichalcogenides (TMDCs) is key for electronic device applications.
• Surface charge transfer doping offers strong modulation of electronic structures in TMDCs.
• Understanding thickness-dependent transport behavior in TMDCs is crucial.

Purpose of the Study:

• To characterize metallic transport in monolayer and multilayer MoS2 under surface charge transfer doping.
• To investigate the metal-insulator transition (MIT) in MoS2.
• To explore the influence of benzyl viologen (BV) doping on MoS2 electronic states.

Main Methods:

• Surface charge transfer doping using benzyl viologen (BV) molecules.
• Characterization of transport properties in monolayer and multilayer MoS2.
• Electrical measurements under varying gate voltages.

Main Results:

• Metallic behavior in MoS2 transitions to an insulating state under negative gate voltage.
• A metal-insulator transition (MIT) was observed in both monolayer and multilayer MoS2.
• In multilayer MoS2, doping effects evolved from the surface layer to deeper layers with gate voltage variation.

Conclusions:

• The study elucidates electronic state details and transport behavior under surface doping in MoS2.
• Observed MIT in MoS2 provides insights into phase control via carrier modulation.
• Findings are valuable for understanding and utilizing thin-layered materials in electronic devices.