Deep-ultraviolet-light-driven reversible doping of WS2 field-effect transistors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Advanced performance in field-effect transistors (FETs) and optoelectronic devices relies on improved electrical and photoelectric properties.
• Tungsten disulfide (WS2) is a promising 2D material for next-generation electronics.

Purpose of the Study:

• To develop a doping technique for significantly enhancing the electrical and photoelectric characteristics of WS2 FETs.
• To investigate the reversibility and underlying mechanism of the doping process.

Main Methods:

• Application of deep ultraviolet (DUV) light irradiation in a nitrogen environment to single-, bi-, and multi-layered WS2 FETs.
• Analysis of changes in charge carrier density, mobility, and photocurrent response.
• Characterization using Raman spectroscopy to observe shifts in E and A1g peaks.

Main Results:

• DUV light treatment in nitrogen drastically improved charge carrier density, mobility, and photocurrent response in WS2 FETs.
• A shift in threshold voltage and Raman peak positions indicated an n-type doping effect.
• The doping effect was reversible, with pristine characteristics restored by DUV illumination in oxygen.

Conclusions:

• DUV light irradiation in a controlled gas environment offers a stable, effective, and easily applicable method for enhancing WS2 FET performance.
• This technique provides a pathway for optimizing WS2-based electronic and optoelectronic devices.
• The reversible n-type doping mechanism opens possibilities for tunable electronic properties in 2D materials.