Engineering of Antisite Defects in CVD- Grown Monolayer MoS₂ via Proton Irradiation

Here, we present a comprehensive joint experiment–theory study on the generation and manipulation of individual point defects in monolayer MoS₂ for the first time by varying the proton irradiation energies between 150 and 590 keV with fluences of 1 × 10¹² proton/cm². We discovered that both the density and the nature of defects can be modulated by the proton energy; a high defect density was observed with lower proton irradiation energies. By changing the energy of irradiation, antisite defects were selectively generated for the first time via proton irradiation. This result provides an alternative way to modulate the gas absorption and magnetic properties of MoS₂ through antisite doping.Other morphological characteristics of MoS₂ were modulated by varying the proton irradiation energy. Raman modes or the PL characteristics were not affected by radiation induced defects. Molecular dynamic simulation confirmed that that the formation of defects can be controlled using various particle irradiation energies. This work inspires future research of defect engineering in tailoring the chemical, morphological and optical properties of MoS₂ as well as other 2D materials to establish more stable and reliable optoelectronic devices for space, defense and energy applications.