Tailoring the transfer characteristics and hysteresis in MoS₂ transistors using substrate engineering

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Molybdenum disulfide (MoS2) is a promising 2D material for next-generation electronics.
• Understanding and controlling charge transport phenomena in MoS2 field-effect transistors (FETs) is crucial for device applications.
• Hysteresis in MoS2 FETs can hinder reliable device operation.

Purpose of the Study:

• To investigate a novel form of transfer characteristics in substrate-engineered MoS2 FETs.
• To analyze the origin and behavior of hysteresis in these devices.
• To explore methods for tuning MoS2 FET characteristics.

Main Methods:

• Fabrication of MoS2 FETs with engineered substrates.
• Electrical characterization of device transfer curves under varying conditions (gate voltage range, stressing, sweep rates).
• Temperature-dependent measurements to analyze hysteresis suppression.

Main Results:

• Observed robust hysteresis with stable threshold voltages and a large gate voltage window in engineered MoS2 FETs.
• Hysteresis was suppressed at low temperatures.
• Inferred that hysteresis originates from charged traps at the MoS2-SiO2 interface, acting as Coulomb scatterers.
• Hysteresis was significantly reduced in devices without substrate treatment.

Conclusions:

• Substrate engineering creates charged traps that influence MoS2 FET transfer characteristics.
• These traps cause hysteresis, which can be screened at high carrier densities.
• The observed hysteresis is an extrinsic effect, controllable via substrate modification, offering a new route for tuning MoS2 FET performance.