Highly efficient and stable MoS₂ FETs with reversible n-doping using a dehydrated poly(vinyl-alcohol) coating

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• 2D molybdenum disulfide (MoS2) field-effect transistors (FETs) face challenges with high contact resistance and low mobility.
• These limitations hinder the practical application of MoS2-based electronic devices.

Purpose of the Study:

• To develop an efficient doping technique for thin-film MoS2 FETs.
• To reduce contact and channel resistance while enhancing carrier density and mobility.

Main Methods:

• Utilizing a poly(vinyl-alcohol) (PVA) polymeric coating for non-covalent doping of MoS2.
• Employing a dehydration process to control surface interactions and optimize doping.
• Creating heavily doped access regions in MoS2 FETs.

Main Results:

• Achieved up to 30% reduction in contact resistance and channel resistance down to 20 kΩ sq⁻¹.
• Increased charge carrier density to 8.0 × 10¹² cm⁻² reversibly.
• Observed a monotonic increase in mobility alongside enhanced doping, with a 200% increase in ON-state source-drain current.

Conclusions:

• Poly(vinyl-alcohol) (PVA) doping is an effective, non-destructive method to enhance MoS2 FET transport properties.
• This technique addresses key limitations, paving the way for improved MoS2-based electronics.
• PVA doping offers a controllable approach to boost the performance of 2D material devices.