Defect-engineered electrical and optoelectronic properties of WS2 irradiated with 10 MeV protons

Transition metal dichalcogenides (TMDs), particularly tungsten disulfide (WS2), have gained considerable attention due to their versatile electrical and optoelectronic properties, making them promising candidates for next-generation nano(opto)electronic devices. This study investigates the impact of 10 MeV proton irradiation on the electrical and optoelectronic properties of WS2, focusing on the controlled introduction of defects, primarily sulfur vacancies, which are crucial for tailoring material properties and enhancing their capabilities. By varying proton fluences from 1 × 1013 to 5 × 1014 cm−2 at an energy of 10 MeV, the defect density was precisely modulated. The effects of this defect-engineering strategy were characterized using micro-Raman spectroscopy, low-temperature photoluminescence, and density functional theory calculations. Both electronic (field-effect transistor) and optoelectronic (photodetector) devices fabricated with defect-engineered WS2 exhibited a 24-fold decrease in contact resistance and a fivefold improvement in photogain. These results demonstrate the potential of proton irradiation as a powerful tool for defect engineering in TMDs. The findings underscore the promise of this approach for optimizing TMD-based devices for advanced electronic and optoelectronic applications, paving the way for tailored material properties in next-generation technologies.