Generating immiscible localized WC phase in layered WS₂ upon 15 keV C²⁺ irradiation

Abstract Herein, we report on the insertion of tungsten carbide (WC) phase within tungsten disulfide (WS 2 ) nanosheets taking advantage of the combinatorial effects of implantation of C with low energy irradiation of 15 keV C 2+ ions and generating sulfur vacancies. The x-ray diffraction (XRD) analyses suggest the co-existence of WC and WS 2 hexagonal phases at mid-fluences of ion implantation, typically in the range of 3.5 × 10 15 – 7.5 × 10 15 ions cm −2 . The phase analysis revealed that WC content was highest at a fluence of 3.5 × 10 15 ions cm −2 with ion irradiation of competing electronic (inelastic) and nuclear (elastic) energy losses. The defect-mediated peak can be probed in the Raman spectra, which is the result of numerous point defects (specifically, S vacancies and C as dopants) caused due to the ion irradiation event. First-principles calculations have also been carried out to study the geometrical constructs and electronic structures of WS 2 before and after implantation. The doped C atoms in WS 2 introduce localized defect states in the conduction band with minima at the M point of the Brillouin zone. Interestingly, the model predicts a semi-metallic behavior, especially when C and S vacancies tend to co-exist. Generating an immiscible WC phase within a few layered WS 2 sheets is believed to enhance both the mechanical strength and stability of the specimen apart from the introduction of semi-metallicity needed for desired applications.