The dominant defect types in chemical-vapordeposited (CVD) tungsten disulfide (WS 2 ) monolayers (ML) were regulated through mask-assisted scattered-oxygen-ion (O + ) implantation. A shadow mask allowed for two distinctive implantation regions: directly bombarded and mask-shaded. Upon direct implantation, photoluminescence (PL) was universally suppressed, whereas in the mask-shaded region, PL was enhanced by up to 500% at low doses before suppression at doses of >3 × 10 13 ions/cm 2 . We verified that the introduction of scattered O + ions and low-density structural atomic defects are the two prerequisites for PL enhancement by replacing O + ions with C + ions and eliminating the involvement of physisorbed gases or laser treatment. Density functional theory calculations were carried out, suggesting a possible mechanism for the vacancy-induced dangling bonds in WS 2 . Sulfur-or tungsten-related vacancies create ingap deep trap states, hindering electron−hole recombination. Scattered-oxygen treatment passivates these sulfur vacancies by effectively eliminating these in-gap nonradiative pathways. In addition, it further increases the transition probability by creating more tungsten-dominated states near the conduction band edge through charge transfer. This work demonstrates a facile and successful single-step method to passivate sulfur vacancies with scattered oxygen ions. It has the potential to heal the PL quenching that originated from the intrinsic high defect density in a CVD-grown WS 2 ML.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.