Modification of WS₂thin film properties using high dose gamma irradiation

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Transition metal dichalcogenides (TMDs) exhibit tunable properties, making them valuable for quantum technology.
• Tungsten disulfide (WS₂) is a promising TMD material with diverse applications.

Purpose of the Study:

• To systematically investigate the effects of gamma irradiation on the structural, morphological, optical, and electrical properties of WS₂.
• To explore the potential for enhancing WS₂ properties through controlled defect engineering via gamma irradiation.

Main Methods:

• Deposition of WS₂ on fluorine-doped tin oxide substrates.
• Systematic gamma irradiation of WS₂ samples at various doses.
• Characterization using X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), and X-ray Photoelectron Spectroscopy (XPS).
• Analysis of optical absorption spectra and current-voltage (I-V) characteristics.

Main Results:

• Gamma irradiation decreased crystallinity and increased grain boundaries in WS₂.
• XPS confirmed the introduction of impurities and formation of point defects (e.g., oxygen, carbon, W-O, SO₄²⁻) with increasing irradiation dose.
• Optical band gap reduced with increased gamma irradiation.
• A 1000-fold increase in saturation current was observed after 100 kGy gamma irradiation.

Conclusions:

• Gamma irradiation induces significant point defects and alters the properties of WS₂.
• The observed modifications enhance the electrical properties of WS₂, particularly conductivity.
• This research highlights the potential of gamma irradiation as a method for tuning WS₂ for advanced applications.