Fig. 2

Site-selective generation of defect emission by helium ion exposure. a Optical micrograph of the monolayer MoS₂/hBN van der Waals heterostructure prior to helium ion exposure and full encapsulation. A matrix of 100 × 100 nm fields is exposed with a pitch of 2 μm. A dose of σ = 2.2 × 10¹² cm⁻² is used. b Corresponding spatially resolved and spectrally integrated PL mapping (grayscale) at 10 K. Spectra are integrated for ΔE = (193 ± 5) meV. The spatial occurence of emitters in the range ΔE_L ~ 100–220 meV is overlayed in orange. c Selected spectra taken from b are shown. All spectra reveal emission from \(\,^0X_{1s}^A\) while only irradiated areas reveal emission from localized states X_L. The defect emission is absent in unexposed areas (black spectra and corresponding circles in b)